I nearly got the 5DII, but found out about the AF on it and so I bought a 70-200 2.8 IS instead.
What AF issue on the 5dII are you alluding to please?
The pixel peepers saw that it did not get changed or upgraded so they concluded that they could not take sharp photos with that camera. If you're not a pixel peeper and know how to use a camera, you should be fine.
Well, I am a pixel peeper and I need to be because I get paid for some of the work I do. Micro stock sites won't accept soft images, and my portrait clients aren't crazy about it either. But that is a pretty narrow explanation and not nearly the whole reason.
It is true that the 5dii is pretty much the same AF as the 5D, and the 5d's is nearly the same as my 20D, and like I said before (can't remember in this post or another) but I only like to upgrade if a camera (or lens) solves a problem I've bumped up against, not just because something is the newest best version, or because I think it's "nifty".
So what was wrong w/ the 5D AF? Well, I would personally like something faster. I photograph a lot of kids and the way I photograph them is to let them run around and do their thing. While I am able to get sharp photos, at times I know that I have also missed a few because I did not have an AF system that could track faster or more accurately. Obviously, you don't need it all the time, but if it would help me out, then I should wait for it, right? Others I know who shoot landscape, studio stuff (product or portrait), and adult portraits rarely have a problem with it as they rely a lot more on the center AF point and have time to recompose. Kids are just a bit quicker
Also, the outside AF points are not as accurate. I experience this w/ my 20D, I've experienced it w/ the 5D, and I've heard reports of it w/ the 5DII from multiple people (and photographers I trust, not just some random forum people). If a kid is moving it is really hard to focus with the center point and then recompose (if you want the kid to the side of the frame for instance) and get a crisp shot. Even if you are not a pixel peeper you can get shots that would not be acceptable for prints. As a portrait photographer, you need to make sure your client can print the images you give them at any size they would want.
I actually don't care too much about whether I get 15, 39, 51, or 133 AF points. I'm quite ok w/ 9, as long as they are spaced well and all accurate. That said, I would have liked it if the 5Dii had its af points spaced out a bit more. It always felt cramped shooting the 5D.
So those are the AF things that I was talking about. As I said...they aren't a deal breaker for most people, but for me (even though I really want FF) it was just not enough. Everyone has different needs as a photographer, the trick is to figure out what your needs are and not what someone else (like me) tells you your needs are. If you are considering a 5Dii, I would recommend either renting one, or seeing if you can borrow one from a friend. Heck, if you know someone w/ a 5D you could try that out too. Just see if you like it. If you do and it works for you, then who cares what I thought of the camera
Hope that helps clear up my statement
Edited for clarity (hopefully
) and to add this: in hindsight, even if the 5dii's AF would have ended up being as good as a 1D series, it was still a better move for me to get the lens . The two lenses that I got while I was waiting have made a much bigger difference in my photos than a better camera (even w/ a fast AF and FF sensor) could have ever done.