And briansquibb (sorry to pick on you Brian) might have a similar bias after using a 1D4 in that the 7D AF, based on the comparison to 1D4, gets an artificial downgrade and "appears" to be not much better than the 5D2. There's a name for that in psychology (can't think of it right now) where human perception tends to bunch things together and minimize differences in the context of something much bigger/better.
I bought the 7D and then because it didn't meet my expectations I bought the 1D4. I am still using the 7D and the 5DII as well as the 1D4 - last Saturday I was using all 3 on my shoot - so it was real back to back comparison.
I have always said that the AF of the 7D is better than that of the 5DII. However (possibly because I only use the centre focus point and have had a long line of 9 pointers) I automatically work round the AF and dont hit the problems that others seem to hit - for example that little delay for the AF to lock. Where the 7D works for me is the use of the expansion point for tracking - it is quicker to lock, but there is still a delay. What may not be a problem for me may of course be a dealbreaker for someone else.
However as a package there are several downsides to the 7D which take the edge off the better AF. The first of which is the picture IQ, particularly when cropping ( that applies to all crop cameras) that the bokeh inevitably looks worse.
I can also see the difference in the picture quality too. Put two sharp A3 prints on the table and I can tell which came from the 5DII and which came from the 7D, particularly when low light is involved. This is my perception that the 5DII gives a smoother image, whereas the 7D seems more raw.
I find that people, who have never used the 5DII, are trashing the 5DII AF based on the street reputation alone as are the press. I believe you can only objectively comment on this after some experience of the camera.
The title of this thread is 'How bad if the AF on the 5DmkII really'. From where I stand the AF is not bad at all if you are using the centre focus point, however you will find that the tracking AF on the 7D does a better job for you and definitely the 1D4 is significantly better.
If the question was 'Is the 7D better than the 5DII' I would be much more hesitant. If the 7D was better than the 5DII why does the 5DII sell in such huge numbers? - there aren't that number of dedicated studio people around.
Here is a good example of what the 5DII can do - the A3 version of this is stunning IQ and the colours are sumptuous.
5DII, 24-105@92, iso50, f13, 1/15,