I prefer CS5's interface, but it just seems like Vegas is far superior in rendering. I try to render gameplay footage of COD with it (the game runs at 60fps), I export it as 59 fps and according to fraps it is in fact that fps.
But, it clearly doesn't look at smooth as it should. Where as Vegas renders it at full smoothness.
I've tried playing with WMV, H.264, AVI, Quicktime formats - none of them can obtain the speed I want.