Finally saw it again yesterday (the last time I would have been able to unless it comes to the second run theaters around here, which it hasn't yet).
It felt a lot tighter than at the preview screening, and I could tell they'd lightened up picture (photographically speaking) and color corrected it and all. I didn't notice anything missing, but it felt like it worked better. I am pretty sure Joss seriously edited any Reaver segments, because they felt a lot scarier this time around. I'm suprised there hasn't been more enthusiasm for the soundtrack because I thought it was really good, and managed to keep some of the sound of the series (the fiddle) without seeming quite as western-y.
Anyway, I'm really glad I did get around to seeing it again in a theater. I will definitely catch it a third time if it hits second run.