Interesting that you (David) just inspired (well, more like the final straw but inspired is nicer) me to sell all my DSLR gear and buy an M9 and order a GH2 as my "AF system". For my uses, most camera meet image quality requirements. But I've become far more picky about quality of use requirements. For me, if it's on a shelf it has poor image quality because it's not making images. First, I found myself carrying my Canon 5D2 without the grip. Then I stopped carrying zoom lenses. Then just a 50 1.2 and an 85 1.2. The switch to a rangefinder was a simple one. I need a half decent AF system, so I ordered a GH-2, but the M9 and an EP-2 are happy to share a bag on my personal trips and 80% of my work.
The 5D2 is an amazing thing. I loved it when I got it and I'll miss just a little bit. Prints were stunning. My clients never understood how good it is, but I did. That's why I used it. My stable of L series lenses (9 in all) are the best of their kind (fast, AF primes). They produced images with dazzling detail and wonderful range. However they have, for the last couple of years, begun to get in the way more and more. I'm not sure what piece of new, expensive gear it was that was one lens/body/flash/stand too many, but rather than having the flexibility that unlimited options should give, I became weighed down by the sheer weight (literally!) of my kit. So more and more they stayed at home. I used m4/3 for anything I could, personal and work. It was liberating. I started to wonder how to fill the gaps that m4/3 had in my work with something much, much simpler. Then I revisited the idea on an M9. I'd been leaving the big Canon zooms at home or in the car for months, except in dim receptions where the EP series AF completely fails. But now with the GH2 that's no longer an issue.
My Canon gear is being shipped to it's new owners this week. My M9 and two lenses arrived Friday and my preferred 50mm should be here late this week.
The M9 replaces my 5D2 and three primes. The GH-2 will replace 2x 50D's and zooms. I've just traded a 20kg kit for 6KG kit, with no loss in productivity.
I've got less system flexibility than I've had in years, yet I've never felt this free, photographically.
Gordon