Just got my Motoactv yesterday. I can't give a long term review as I've used it once, but I can give my first impressions. It's huge. I am a bigger guy, 6' 180, and I think it's huge. It's on par with the bigger Garmin watches.
I only have the wrist watch and clip mount, I wanted to make sure I liked it before I bought the more expensive bike mount.
It's really customizable. You can adjust all your workout zones, the information that appears on the screen for each type of activity, etc. It has elevation, gps of course, an FM radio (seems to actually work!), a stopwatch and timer, the music player, maps included for most of the U.S., and much more.
The supplied headphones are okay, and they come with 6 different silicone pieces for your ears, 3 sets that "completely" block ambient noise, and 3 sets that allow ambient noise. They have a built in microphone. I have it synced to my Droid Razr and I can receive texts on the device, as well as answer calls. Pretty cool. The music player is standard Android fare, as is the menus, home screens, etc. You can actually root it, but I probably won't do that.
The online software is okay, I don't see any calorie counting function for managing that, but it does indeed record your calories burned. It can function as a pedometer, and you can calibrate it for indoor running or elliptical machines to measure your distance etc. It found my Garmin heart strap as fast as my Garmin's do, and it will work with a cadence sensor also.
I think if you can handle the size, it's an awesome device. I'm hesitant about it's water resistance, but if I ride in the rain I guess I'll figure out more about that then.