I prefer vegas for editing, because it's faster and more accurate and crossfades are realtime. It's great for surgical type stuff, re-aligning tracks, actually zooming in to check phase and just really get anal. I also like the fact that you don't have to rely completely on your CPU if you wanna get crazy with overloading plugins - you can render any length of chains or any amounts of tracks you want, but it's just won't necessarily be realtime playback in the editor.
I still prefer protools for it's mixing system, the busing and automation is still allot better then the one in vegas, or maybe 'different' is a more appropriate word. And of course it has some MIDI.
What I don't get is why they don't merge Vegas with ACID (and more developed MIDI) and make an all-audio program. That would rock.