You have to be impressed, however, at the form factor of the thing. On-board FTDI and a killer processor in a footprint smaller than an R4, way smaller than a MEGA, and with some serious firepower. No RF, of course, but pretty impressive nonetheless.
The footprint was not a big issue until this recent project (the thermostat) where I wanted a MEGA but my real estate was seriously limited. I ended up with a doubledecker PCB, which was useful for other reasons in the end (getting the LCD and bar display near the top of the enclosure), but smaller is (as you know) always better!
C