again, different systems. The 5D's is more accurate, but center point based. The x0D does have more cross sensors, but they're no good in low light, so that's just better on paper IRL...
Hmmm....I've heard some people (Like PictureCrazy) who love the cros type outer points.
Maybe it's just the winter crankies setting in. Every winter I shoot in low light and I get tired of watching my 85L rumble back and forth from MFD to infinity while the 5D outer AF point tries to latch on to something....anything.
Do you know how long it takes an 85L to make the complete round trip?
The good news is that I put the EE-S screen in my 5D about a month after I got it and my manual focussing skills have improved.
Plus manual focus improves composition because you stop putting everyones eyes at precisely one of the focus points for most of your shots.
It is still slower though.

