I recently bought a M2 after using an M for so long. I am honestly surprised how underrated if not hated these bodies are. They really are gems, but I admit extreme disappointment at the following things:
1. The M2 only has wireless tethering, not wired. It's ok, but not great. Rates about same as Sony A7 and gets a 'cute but not entirely useful' rating from me. How and why wired tethering does not work is a complete mystery to me.
2. Spot metering. JEEZ Canon, this has been a sore subject for so long, let's get that going already!
3. Port door changed and can seriously only be described as 'fugly if not fawkward'.
4. EXTREME disappointment at Canon's lack of commitment to this line, but rumor has it that will change. Curious to see more 'pro' lenses if not bodies. Speed booster would be heavenly too.
5. No Magic Lantern as far as I know. Very sad panda, but hopefully will change.
Will be posting a youtube review online soon, including showing differences between M, M2 and Sony A7. =)