So yeah I ended up getting 3 sets, all small ones. From left to right: USS Kelvin, Klingon D-6 Battlecruiser, and USS Enterprise. They come on these funky little stands which light up when you squeeze the starfleet insignia base.
I noticed a few things about the klingon battlecruiser that weren't very well done (parts that could have been spun around to better represent the shape of certain sections) but then I realized that it's based off the D-6 ship which got like 30 seconds (maybe) of screen time in the 2009 trek movie, and not the classic D-7 ships from TOS. So that made more sense. Even so, I ended up moving a few parts on each model to make them slightly more correct.
The Kelvin is probably the most accurate of the three (and also the smallest piece count) because it's hard to mess up a saucer and two tube-like structures. My biggest complaint is the saucer's un-needed thickness and the squareness of the warp engine. But otherwise, you definitely know what ship it (and the others) are supposed to be.
In terms of quality, the parts stick together fairly well. Having had experience with both megabloks and best-lock, I can say these seem to be slightly better than both (though in fairness megabloks seem to be getting better). The ships stay on their stands, the parts mostly fit (a few slight gaps here and there) and they're nice little representations of some great ships.
Each of these cost about $10, and I was pretty happy with them for what they were. Not really screen-accurate by any means, but they're valiant attempts and nice desk models (and as I said those stands are pretty sweet). My biggest beef with these is the many things on the Enterprise model that could easily have been fixed to be more screen-accurate - like the needlessly wide engineering hull, the warp bussards being on the top of the engine rather than the front, things like that. But most of you probably wouldn't have cared all that much.
I did some tweaking to prove my point, and while it's not as good as it could have been because most of my lego's in storage, it does represent the ship a bit better and there's no reason they couldn't have done it more that way.
Anyway, these were fun and cheap, and I'd recommend them to any lego-loving trek fan even just for the novelty. I hope hasbro makes more ships like this when the next film rolls around - I'd love a miniature USS Vengeance!