Well, thanks to a receipt from TRU that gave me three dollars off a purchase, I caved in and bought both the AAT and the Vader JSF (or SSF) yesterday. I hadn't planned on getting Vader's fighter, as it's not even in my realm of EU acceptance (I'm pretty much a six films and Clone Wars type of person), but the photo on the back made it seem pretty cool.
And cool it is. I'm a big fan of the ROTS JSF designs, and while the huge Imperial logos on the top wings are a little gaudy, and the huge red Imperial logo stickers alongside them make it somewhat redundant, the ship does look incredibly cool. Something that a lot of photos (and the ones on the box itself) don't really show all that well so far is the canopy and TIE-style window in the cockpit are red instead of the regular clear "glass." This makes the ship look extremely sinister.
My only complaint is, once again, with the labels. The labels in the cockpit are, like the other JSFs, an absolute pain to get in correctly and uniformly, but the worst of them all are the droid body labels. Even though the Anakin and Obi-Wan mass market JSFs' droid labels were done well, the Mace and Obi-Wan TRU JSF's droid labels are way too large for the body. This continues with Vader. I seriously gave up trying to exacto-knife the labels down to fit correctly, and it looks just as good with a solid unlabelled black body to me.

But hey, at least there is a Vader available at retail that can actually sit in the cockpit, which is more than I can say for the Kit Fisto/Saesee Tiin JSF models.

The AAT, strangely enough, is such an improvement over the Episode I version from 1999 that it's not even funny. The E1 version always felt very fragile to me, with the two cannons on the side of the body always seemingly in danger of falling off, and the cockpit cover being on a hair trigger. In other words, it is a nice piece to look at on a shelf, but not very sturdy.
The new version, however, is extremely sturdy. Hasbro got rid of the stupid cockpit launching feature (they may have done this on the 2003 Clone Wars version too, in which case I might need to track one of those down if it's as sturdy as this new one), and the quality of plastic on the side gun arms is much improved since the 1999 version. Like the JSFs, though, the stickers do require a bit of creative Exacto knife usage to fit correctly, but nowhere near as much.
The best thing about the new version is the paintjob. It's incredibly dark, much darker than what the photos on the box lead you to believe. Where the 1999 version looked fresh off the assembly line (aside from the scoring along the missle launchers), this new version has seen plenty of action. Tons of silver metal scrapes, lots of scoring, and (fictional) hints of the vehicle's paint wearing down in areas make this vehicle one of the best jobs Hasbro's done with a vehicle repaint in a long time (probably the best EU update since the Saga A-Wing, if I may be so presumptuous).
It's actually kind of sad that the second wave of vehicles in 2007 is going to be yet another JSF repaint with no corresponding figure and a ridiculously underscaled repaint that nobody wanted to begin with. These three vehicles (including the Hailfire Droid, which is also really well painted) are all well worth picking up if you're a fan of vehicles, but if you have to get just one, pick up the AAT for sure.
At this rate, I'm going to need to set up another whole set of shelves for just the EU Clone Wars vehicles which, by and large, have been consistently great.