I already know Canon is best, but...
I was talking to a guy who with a partner have their own fine art portraiture, fashion and family portrait business. They are kept busy shooting online fashion photography and portraits.
Well this bloke has just sold his 7D and now shoots with the Olympus OM D. Both guys shoot with this camera and love it. He said the focus speed is the best in the business, including the 1D-X (well about level) but easily beats the 7D and just about anything else. IQ is superb, video is better and when he needs access to full frame, he only grabs it rarely now for landscape purposes but the little OM D does that pretty good as well.
http://www.adorama.com/IOMEM5S.html

Lenses adapt to it easily and via an adapter and weatherproofing is very good. Lenses are very good quality and a lot cheaper than red ring lenses, but you can use them if you grab the adapter.

Has anyone looked at these yet?
Is anyone considering something like this?