I came from the HTC Incredible (first version) to the "M," and use the device similarly to what you describe. I like the smaller size of the M, and that was a major factor in my decision (also looked at Razr Maxx, S3, and others - all of which are larger form factor). On my old Incredible, I would plug it in for charging whenever I could since the battery drained quickly (email set to push). My M often still has 50+% battery at end of day without any charging. Sound quality on calls is as good as any cell phone I've used, but I'm not an audiophile. My M has never crashed in the about 4 months I've had it.
It takes a couple of days to get used to the operating system changes and interface, but the M does everything the Inc did. The only thing I miss from the Inc is the time/weather widget with the lightning, rain, etc. animations. The "M" has a similar widgit - functionally - called Circles, but it doesn't have the animations.