What I like best is things like when maemo mapper 2.6 didn't work with my N800/OS2007 setup then it was just a matter of dumping the source to disk, adjust the code, build and install and I had a working maemo mapper again, before my trip to unmapped lands. I couldn't do this that easily with any other mobile device I've owned.

In other words: The community is good, and the open aspect of Maemo is good, and I believe the former is made possible by the latter.