The mobility support guy at my office recommends a factory reset after any major update of software as a matter of course. I do know that since an OTA update to ICS carries over a lot of data and settings, that were determined by an earlier version of Android, any problems you had could linger if they were due to settings or preferences. A factory reset certainly does reset your phone to a state that is exactly what the provided update image is, so it doesn't hurt the phone to do so -- it primarily hurts YOU by forcing a lengthy process of re-installation, particularly if you have security apps that have to be re-provisioned (RSA Softoken, Google Authenticator, Secure EAS or Touchdown, etc).
Me, I was loathe to lose game progress and such just to upgrade to ICS, so I'm happy that the T-Mo ICS update for the Amaze didn't wipe everything. But at some point in the future I will probably do a factory reset and reinstall of applications JUST to clean out the phone storage of cruft left by apps I've uninstalled. System will probably run better just from that alone.
Postoid is not describing a reset, just RESTART (aka reboot).
Cyanogen-man, your lack of punctuation or capitalization makes it it painful to read what you're posting. I couldn't read it. If what you have to say is worth writing -- and readin -- it's worth doing it proper so that it's not difficult to read.