The AMT/ERTL kit is OK, no more no less. There's still a lot of work involved, particularly in thinning down both leading and trailing edges of the big wing... I have here the 1962 kit of the Valkyrie by Aurora (in fact it's the re-edition from '69). I got it on e-Bay for a decent price but unfortunately, the kit is not 'workable'... Being designed even before the real thing flew, the kit has many major mistakes... If you picture the wing as a big triangle, the height of the kit's triangle is about 6cm too short, while the base, ie the span of the wing os spot on, scaled at 1/100. Re-building the wing is itself a major project! On to of that, the fuselage, from the tip of the wing to the tip of the nose, the fuselage is also about 6cm too short... So all in all, there's 12cm of lenght missing..! That's only two of the major mistakes of the kit.... So, unless you are a collector and can get the original '62 box, do not bother!
There are vacuform kit i 1/72 and even 1/48 I believe!!! All of the above depicts the first aicraft (serial 20001); Major work to build A/V #2....
And of course both Trumpeter and Panda are releasing the 1/32 kit in 2004....