Hi Alex,
First, let me point out several excellent sources for your investigation:
1) don f started a very extensive and detailed forum thread on the Hasegawa B-24D at the Aircraft Resource Center website. I highly recommend it to you:
http://www.arcforums.com/forums/air/index.php?showtopic=155278&hl=hasegawa+b-24d
2) Paul Boyer has a very nice build and review of the Has. B-24D in the current issue of Finescale Modeler (July 2008).
3) Nick J. Wigman has a more in-depth build (ie, lotsa photos) in the May 2008 issue of Model Aircraft International. Really very inspiring!
4) Libor Jekl just posted the Has kit built up as a Liberator GR V on Hyperscale a couple of days ago:
http://www.clubhyper.com/forums/plasticpixframe.htm
5) And of course, you should read Nick Pearsall's build at IPMS/USA's website:
http://www.ipmsusa2.org/Reviews/Kits/Aircraft/Kits_Air.htm
I want to give credit where credit is due, and give you some places to look at built-up examples of Hasegawa's new kits.
That being said, from my perspective, the Minicraft/Academy kits are nice, but the Hasegawa kits are the bee's knees. For now. With any luck, RoG will take notice, and in a couple more years, we will see a new generation of reasonably-priced B-24s. No kit, including Hasegawa's are perfect.
Generally speaking, the Minicraft/Academy kits suffer from two main flaws: undersized engine nacelles, and undersized turrets. I have represetative example of every 1/72 B-24 ever produced: Revell, Airfix, Matchbox, Academy, Hasegawa. Every one of them (except of course, the PB4Y-2, which has a different engine arrangement altogether) have engine nacelles that are the same size except the Academy kits, which are noticably smaller diameter affairs. This is not exactly new or even controvesial news, as Ron's Resins long ago produced a set of correct-sized engine nacelles for the Academy kits, which are now being produced and sold under the High Planes label. Apparently, the wing fairings are correctly sized - you just slap on replacement nacelles and you're good to go. For that matter, one could use Revell or Airfix nacelles, suitably cleaned up and detailed.
The nose/tail turret issue is something else, though. Again, Revell, Airfix and Hasegawa turret assemblies are pretty much the same size-wise, but the Academy nose and tail turrets are noticably smaller. The tail turret so much so that the fuselage is about 2 mm shorter, and a little pinched to accomodate the smaller sized turret. This can be at least adequately addressed by extending the turret support about 2 mm, and using a larger turret, preferably from somebody else's kit, as the shapes leave something to be desired.
There are, of course, the usual host of lesser issues, for example, the Emerson-turreted B-24H contained nose parts characteristic of the Consolidated-turreted B-24J, and vice versa. The tunnel gun windows on all the Academy kits are molded as part of the fuselage, and not opened as on the Hasegawa kits. The Hasegawa landing gear are more accurately molded, although the Academy LGs could be modified.
Still, with sufficient attention to detail, one can build a credible B-24 form the Academy kit. And it is still a fraction of the cost of the new kid in town.
Now, the Hasegawa kit:
State-of-the-art 2008 level detailing. Very impressive. The control surfaces, particularly on the horizontal and vertical stabilizers appears more realistic on the Hasegawa series than those of the Academy, although this complaint can be equally applied to thier B-29/50 series, as well. The waist gun wind deflectors are accurately portrayed on the Hasegawa kit (at least in the closed position), but only scribed into the Academy series. The tunnel gun windows are opened, with clear windows.
The thing that really got my attention, almost as soon as I opened my -D (and oh-by-the-way hooked me to spring for the -J, P.T. Barnum or no!) was clear sprue F, whcich contained not only two Consolidated A-6B nose/tail turrets, but an absolutely gorgeous, properly-shaped, to-die-for Emerson A-15 clear top. A little more investigation revealed the parts to build the entire turret, consisting of at least 11 separate pieces, internal framing, armored glass, and even the lower tub!!!!! Mind you, nobody, in any scale (well, other than the '50's Revell box-scale kit), has ever molded the Emerson turret glass parts in a single casting - it's always molded in two halves, leaving a very unsightly seam down the middle of the turret. Impossible to fix - even Falcon refused to mold a replacement for the Academy kits, stating that the piece would be too deep to vacuform. And Hasegawa got it in one!!!!!!
Similar to the Academy offering, Hasegawa offers flat and 'blown' sliding canopy section, but the Hasegawa pieces actually look 'blown', while the Academy pieces simply look like blobs.
As I mentioned above, the Hasegawa -D has all the pieces to allow you to install a ball turret if desired, although the instructions don't tell you how to do it. This does provide a level of flexibility above that of the Academy -D, which only allows you to make an early, non-ball turreted B-24D.
Additionally, the machine guns are very, very nice. All of the turret guns come complete with the wind strips appropriate to the particular turrets, including the top turret!
Sadly, though, not everything is perfect in Hasegawa land:
Several of the posts I quoted at the top detailed some of the more obvious compromises that Hasegawa made to kit multiple versions of the B-24. In reality, the Academy kits suffer from many of the same compromises.
The Consolidated A-6B turrets are not detailed to the same level as the Emerson A-15, although they are head and shoulders above either the Airfix or Academy equivalents. All versions of the Consolidated/MPC hydralic turrets had a definate internal structure that Hasegawa simply did not capture. Basically, A-6 turrets enclosed the gunner in a smaller interior 'shell' over which the larget turret plexiglass rested. On the plus side, the Hasegawa glass part is thin enough that one could srcatchbulid these two sides without too much angst. Moreover, the fully-enclosed A-6B tail turrets did not appear on -D series Liberators, at least not in the tail position. (a number of Pacific Theater B-24Ds were both field and depot modified to incorporate the A-6A turret in the nose, and these are clearly fully enclosed units. As a side note, if you want to model one of these Liberators, use the Airfix nose, which correctly has the B-24D nose line, entirely different from production -Gs, -Hs, and -Js.) At this point, there is no really good open A-6A tail turrets on the market, although this could change in the aftermarket world. An absolutely fantastic 'open' A-6A turret was included as a part of Cobra Companiy's PB4Y-2 conversion, but unfortunately, Cobra Company seems to have closed their website again. Hopefully, this will be only temporary, and we can convince them to produce those tail turret parts as a separate release.
The tires are, as have already been ponted out, are 'way too flat. The tread detail is lacking, too. I would either build up the bottom area with Evergreen strips, or replace with Academy or True Detail wheels. Doubtless, one of the Czech aftermarket companies will be offering some soon.
I'm not at all sure that I agree with Hasegawa's interpretation of the bombadier's station. At least Academy included a Norden bombsight.
Academy, while molding the tunnel gun windows as part of the fuselage, provided a reasonably accurate tunnel gun door/mount, which is molded as part of the fuselage in the Hasegawa kit (who molded the tunnel gun windows clear!?) You need to use the Academy piece for an early -D. Fortunatly, this particular piece appears in every single Academy version of B-24, so there's plenty to be had!
The engines are somewhat generic, but Quickboost has already released 'drop in' replacements, for both Academy and Hasegawa kits. Alternatively, you could simple spruce up the engines yourself - thy're not really that bad.
The Hasegawa B-24J is identical to the B-24D, with the exception of clear sprue J, which contains the two halves of the -J nose. The nose turret wind fairing looks as if it is the Emerson fairing, (and suspiciously similar to the Academy shape, which isn't quite right but can be fixed relatively painlessly) rather than the Consolidated wind fairing. It's not mentioned in the instructions, but Hasegawa has provided three different upper nose window configurations. The upper nose windows, as molded, are the flat rectangular type. However, you can cut them out and replace them with either 'blown' rectangular window inserts or 'blown' oval window inserts. Additional flexibility. The bottom section of the nose pieces look as though they might be pre-scribed windows for the F-7 Photoreconnaisance version, but I haven't quite decided on that one yet.
It looks very much as though one could mix and match nose parts from the Academy kits with the Hasegawa kits, although one would also have to use the Academy cockpit canopies, as the Hasegawa versions are molded integral with the top portion of the nose parts. (this is a particularly nice feature, as it allowed Hasegawa to integrally mold the navigation blister, and it turned out a lot thinner and clearer that if it would have been molded as a separtate part!) That might not be the worst thing in the world, either, as there were several syles of B-24 canopy framing.
So, from my perspective, I really like the Hasegawa kit, but have seen some really nice Academy B-24s built up, too. (B-24Ds, at any rate) No matter how you cut it, though, if you're going into the nose-turreted B-24 business, you're going to be wanting some Hasegawa turrets (especially those really nice Emersons), and anybody else's engine nacelles, at a bare minimum. With the two of them together, I see the potential to add serious flexibility to the ability to model the B-24 series, and that can't be a bad thing!
Now, for a brief "pox on both your houses" diatribe:
1) Nobody makes parts to allow for accurate modeling of late Pacific Theater B-24s, almost all of which were depot-modified to remove the ball turret and replace it with a lighter arrangement of twin .50s on a scarf and ring mount, with additional 'tunnel gun' windows added right above where the ball turret used to be. It's a pretty much standard mod, and even appears on 'Cocktail Hour', Hasegawa's main version of the -J. Ahhrrrgggg! (sound of gnashing teeth here)
2) Nobody makes even a crude representation of the light hand-held tail turret fitted to late model B-24s, again, mainly serving in the Pacific. It's a fairly complex affair, and my hat's off to the modeler whose skills are good enough to fabricate by hand. Mine aren't.
3) Arguably, the Academy B-24M has something that kinda looks like the (in)famous Ford S-Nose, but it's the only one that does. Not so frustrating to me, as all the B-24s I personally want to build didn't actually have the S-nose, but a whole bunch did.
Hope this helps.
Byron