To make my VAS, I was more worried about the lack of weapon options in the normal assualt box, so I bought a normal tactical sqaud box and used them with the boatload of jump packs that I stockpiled to make a unit with interchangable arms (magnetized) that could have standard bolt pistol/chainsword kits or be able to take power fists, melta guns, flamers, etc. Since the tactical box comes with flamers, a melta, a plasma gun and a power fist, all I need to do is find other bits, like thunder hammers and rig them with magnets. Then I'll have any number of WYSIWYG options for the Vets.
Another good point to this approach is that I got 10 figures instead of 5, so I can have a full 10 man squad for a little less than the Assualt Squad box of 5. (Of course, I already had the extra jump packs so you're savings may vary)