I continue to be amazed with the IQ of my M8. Sure, it has its quirks and limitations but it is still a great camera. At $2,000 or thereabouts used, it is a bargain.
Mine has been a faithful friend and constant companion for the last 3 years. It has produced some of the best images I've ever shot. The MP count, crop sensor and filters have never proved much of an issue. I get good 24x36 inch prints from my M8 files - prints that have the WOW factor.
Do I want a M9. Of course I do! And I'll buy one. But for now, I can happily "make do" with my trusty old M8.
Tom