** These CyanogenMod builds are highly experimental and unsupported. ** ** Please refrain from submitting bug reports for any issues ** you may encounter while running one of these builds. ** ** Submitting bug reports on nightly builds is the leading ** cause of male impotence.
since i am a bit idle right now, i try to answer this.
cyanogenmod is the only open source rom, that runs on 40+ different devices. we got around 45 devs (people who really write code and tweak things to make it work better - in contrast to cooks, who only use winzip to exchange this vs. that binary thingie) constantly making cyanogenmod better.
as background, you might wanna know, that google usually releases the sourcecode to their products (where honeycomb is the first exception, but thats another matter, ICS will be open source again). but when google releases their source code, you cannot compile it for ANY phone and it runs on it. thats the first part, we jump it - make it compatible with all the phones we support.
once it basicly runs, its time for what we call "cm extras" - we modify a lot on the gui and the system to make it run better. some stuff you as a user will never see involving tweaking libs and kernels, and some stuff you as a user will see a lot, like including theme manager, dsp manager, cm settings (cm settings are about as huge as the normal settings are). those settings range from simple "dont display clock in status bar" to complex profiles (as known from old nokia phones) or remapping of some keys (long press home, remapp search button behavior)
its way to much to list it all here, but i can assure you, cm is fast, usually stable on most devices and VERY VERY customizable - both in grafical ways as also in behavior way.