I updated to JB with the OTA update several months ago. I did not do an FDR as I did with ICS. I thought my Bionic ran just fine without it. However, after a few months use some of my apps started acting up and the phone just got slower than I thought it should. With all the rain from tropical storm Andrea yesterday I had nothing to do so I decided to finally do an FDR. I backed up all my data, photos, music, etc with My Backup Pro as well as copied to my computer just to be safe. I did the FDR and just loaded apps back that I really needed and wanted. I haven't checked the battery life yet but man this phone screams now! The apps that loaded slowly before now load very quickly and operate much more smoothly. Some of the apps even look different even though I updated them before the FDR. If you have any doubts about doing a FDR don't wait. It is well worth the trouble. My contract is up on my Bionic next month but now I don't see any reason to get a new phone. I will keep this one til it dies!
Old thread I know, but I'm one that STILL has his Bionic lol. I'm about to pull the trigger on a G3. All I can say is that after several FDRs, the phone eventually goes back to being a brick. It's so slow it's practically unusable sometimes and when you need it the most. Don't have time to constantly be FDRing it. It'll make a good backup phone in case of loss, theft or breakage.