I'm half tempted to pick these up as well, we'll see. I don't have the earlier versions of either, but at the same time I don't have a lot of display space left for vehicles - and the OT ships I have take precedence - so with the AT-AT, and possibly a Snowspeeder coming later this year, space might be at a premium.
Anyways, looking at these, I might pick up the AAT, that looks pretty nice and I kind of like that ship. We'll see about the Hailfire Droid. I do like the Vader Starfighter, and I hope to pick that one up. I'm just a fan of that starfighter design in general, that's a pretty nice ship.