yesterday I installed russian 2.3.6 over odin.
My thoughts are.
The swipe to unlock is much better. Before was too hard on 2.3.3.
So far early indications are battery life is improved but only had it on 12 hours at the moment.
In terms of preserving apps/data, I had previously setup sd-ext for apps with a cf-root kernel as well. When the upgrade was done I was unrooted and apps not available (other than system apps), after cf-root was reinstalled all my apps were back, in addition all my contacts etc. were preserved. However I did have to do some manual work to get a2sd fully functional again, with a2sd as the a2sd binaries were missing so I couldnt adjust settings, wipe dalvik cache use the gui a2sd app etc. But someone not using sd-ext wouldnt have these issues, and in the end turned out minor work to fix.
However defenitly do a nandroid backup first before you start so you can roll back if you need to, by that I mean a CWM backup. Also put the backup on your pc as well incase something happens to the SD card.
