No, there are no speed launchers this time, and it takes the forementioned 2 seconds to launch only on first launch. It seems to stay prefetched or cached after that, though, and loads instantaneously on subsequent loads for a while until it gets flushed again.
But AFAICT, that's Vista's doing.
Sorry to disappoint you
Edit: Oh, and it doesn't seem to freeze/crash Firefox anymore and loads big PDF's a lot faster.
Edit2: And yes, i actually hate Acrobat as much as the next guy, but this time the code monkeys at Adobe seem to have done their homework