For me the idea of a small and lightweight DSLR seems quite attractive. I have used and worked with Sonys NEX-5 and have to say that I really prefer to look through the lens and not on a screen to compose pictures. That is why I am not really interested in the Canon EOS M either.
Get a good digital viewfinder and you're set, hence the NEX-6
5D3, 5D2, NEX-6 | SY14mm f/2.8, Ʃ20mm f/1.8, 24mm f/2.8, 35mm f/2, Ʃ35mm f/1.4A, 50mm f/1.8 I, Ʃ50mm f/1.4 EX, 100mm f/2.8L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: SY12mm f/2, Ʃ19mm & 30mm f/2.8 EX DN, 16-50 & 55-210 OSS | 2x FT-QL, AE-1P, FD(n) & FL primes