I did tried the stable cssu and didn't see anything different and then I tried the testing cssu i noticed the portrait mode and camera ui changes, portrait mode was a nice but most app was just opened in landscape mode, which made the portrait mode kinda silly and the cssu did break the sketch app on my device. In the end I decided to reflash the device and just installed kernel power and few other necessary apps, and unstalled most of the pre-installed games and widgets that i don't need. I've using n900 for 2yrs and my device have never shutdown on its own. The longest uptime i remember that I had was about six months and all others was just me rebooting the phone after messing with the system.