Very interesting indeed! On the basis of the pictures in that review - which admittedly don't show up as clearly as they might on my little home monitor - I'm inclined to think the two kits are close to equal in quality.
The Revell one has wood grain (extremely well done) and perhaps somewhat superior exterior hull planking. Emhar indicates the butt joints between the ends of the hull planks; Revell doesn't.
I'm a little confused by Jorit's reference to the keelson; maybe there's a nationalistic difference in vocabulary here. I'm used to thinking of the keelson as a longitudinal structural member that runs parallel to, and above, the keel - usually clamping the ship's frames between it and the keel. By that definition the Gokstad Ship doesn't have a keelson - and both kits are correct in not having one. But I'm wondering if Jorit is using the term in a way with which I'm not familiar. Maybe the part in question is the "crone" - the enormous piece of oak that sits on top of the deck beams amidships, through which the mast is inserted. (Let's not talk about where the name - which is also sometimes translated "the old woman" - came from.) In the real ship there are in fact two rather similar pieces, one (through which the mast passes) above the deck beams and one (in which the mast is actually stepped) sitting on the keel. Revell cast a nice, well-proportioned replica of the upper one integrally with the deck, and omitted the other one. (There's a simplified mast step molded in with the hull halves.) The lower one can only be seen if the deck planks are removed. I personally find Revell's approach to the problem more than acceptable, but it looks like Emhar's may be a bit superior. I agree with Jorit: it would be nice to have the option of omitting some or all of the deck planks. (In reality they're just short pine boards, laid loosely and temporarily in rabbets on the upper edges of the beams.) It looks like that would be relatively easy in the case of the Emhar kit; doing it to the Revell one would entail adding considerable detail to the inside of the hull halves.
None of the photos shows the inside of the hull halves, so I can't comment on how Emhar handled what I consider to be the biggest problem with the Revell kit: the knees on the ends of the deck beams. Revell molded them (sort of) split between the (one-piece) deck and the hull halves, with not really satisfactory results. (The first thing I did to my Revell kit, once I had the deck and the hull halves together, was to make my own "deck beam knees" with Milliput. So far so good.)
One of the first things I did upon opening the Revell box was to throw out that hideous decal that was intended to go on the sail. I confess I don't care much about the thread or the rigging instructions either; absolutely nothing is known for certain about the Gokstad Ship's rigging - and I think we can be pretty certain that she didn't have a primitive caricature of a character from a Wagner opera painted on her sail.
The Emhar "sail" itself doesn't look particularly inspiring, but it's hard to judge from the photo.
I rather like the bow ornament on the Emhar kit. It appears to be based on the carvings found on a folding bed in the Gokstad tomb; thus it's certainly contemporary with the ship, and at least believable as a bow carving.
I'd have to see those Emhar shield rows to form an opinion, but it sounds like it might be an acceptable solution to what many modelers - and wargamers - might find a problem. I imagine a wargamer would find it easy to knock 64 individual shields off.
Emhar apparently cast the tiller as a separate piece; Revell rendered it as a plain "stick" cast ingegrally with the rudder. That's a rather important point, as the tiller of the Gokstad Ship is the most elaborately decorated surviving component of the ship (and the only one with gold leaf on it). [Later edit: as it happens I was working on the tiller for mine this evening, and took a close look at a color photo of the original. I think the substance in question is yellow paint - not gold leaf. But so little is left that it's hard to tell.] Score several points for Emhar.
On the other hand, it appears in the photo (I can't tell for absolute certain) that all 32 of Emhar's oars are the same length. The Revell kit correctly provides oars in four different lengths. (They almost have to be made that way; some of the oar ports are higher above the water than others.) This would be an easy problem to solve.
The Revell kit scales out (by length) to about 1/63. (I'm going by memory here; I measured the hull some time ago and the piece of paper I wrote the figures on is in the shop, but if it wasn't 1/63 it was in that neighborhood.) [Later edit: I did the arithmetic again. The scale works out to 1/63.3.] I did by a set of Emhar "Viking Warriors," who scale out to about 5' 6" tall on the scale of the Revell kit. That is, as we established in another thread, certainly believable.
If I were starting fresh on a Viking ship model I'm honestly not sure which of these kits I'd pick. Probably the Emhar, but I'm not sure. So far I'm not inclined to throw my current Revell project in the trash and rush to order an Emhar kit - but I haven't seen the Emhar one "in the flesh" yet. I reserve the option of commiting X-acto hari-kiri.