yes, i have updated my firmware to the latest nokia offered pr1.2. ive installed some tweaks to prolong my battery life, installed kernel-power by titan and used ideal setting and now my phone last 2 - 3 days, for MMS i installed fmms, for installing apps, i used faster app manager, for audio video needs i installed extras codecs, tomamp and smplayer.

if u are experiencing lagginess during call, you could lurk in the forum and search for "optimize your n900". its a script that would clean your n900 as if u did a restart.