I met up with a buddy of mine this weekend who is the editor of a big muscle car magazine to cover an autocross event together. He's a very accomplished photographer and does some outstanding work. During the middle of the autocross, his 1DsII - which has seen a ton of mileage over the last 8 years - took a dump. It's nothing terminal, just the dreaded "Error 99," but something that couldn't be fixed in the field. I let him borrow one of my backup bodies to get him through the event, but he jumped on the phone ASAP to order up a replacement body for another shoot he had the following week.
Him: The guy on the phone says he has a 5D Mark II, is that what you have?
Me: No, I use 5D for statics, and a 1DII for action. I'm getting a 5DIII any day now, but it hasn't been released yet.
Him: What's the difference?
Me: Better AF, faster burst rate, cleaner high ISO files, dual card slots.
Him: Well, I hardly ever use AF, and don't need fast FPS. I really like the IQ of the images you send me with your 5D, so I'm sure the 5D Mark II will be more than enough for me.
Me: Yeah, IQ wise the 5D Mark II is a great camera. That's what Bobby (a mutual friend and fellow photog) uses.
Him: OK, then I know for sure that I'll be happy with the 5DII's IQ.
Me: You can get them for around $2,000 right now because the 5DIII's are about to be released. The 5DIII is hard to get right now and costs $3,500.
Him: I don't want to spend that much. This is just going to be my personal camera until I can get company approval to expense on new body. I'll go with the 5DII.
I know this is an extreme example, but our conversation lasted two minutes at most. I just found it funny how people can deliberate/argue/scream/cry for months on which camera to get, mulling over specs and sample images (I'm guilty of this too!). On the other hand, I watched as a working pro reached a purchasing decision in two minutes based solely on the quality of images submitted to him from other photographers using the body he's interested in.