Actually, another feature of the new M is very important to me: responsiveness. According to every reviewer who has actually handled a live one, the speed with which it writes and displays data is yards better than the M9. The M9 is a lot more responsive than the GXR but has nowhere near the responsiveness of the Olympus E-5 that I sold. I've knocked into the "can't shoot because I'm writing data out" limit a couple of times now with the M9 and the somewhat lethargic way it pulls up images in review mode reminds me of the E-1. (The E-1 bangs into the 'locked buffer write' situation less often because it has a larger raw buffer ...) The new M will write fast enough, according to all reports, to be on par with the E-5—which I never did get to hit the buffer write limit in real use.
Of course, what the new M's sensor does compared to the M9 will be an interesting comparison. I suspect, however, that it will be a toss up there, and the improved dynamic range and sensitivity a plus.