Using iPhone 5S Upgraded from 9.3.4 to iOS PB4 OTA, didn't reset settings & data Performance is really great ! Using as my daily driver, I mean on every aspects of the system. Everything goes smother, and quicker. Even games performance seems to be better. I also notice that iCloud backups takes now (much) less size. You can now use the triple home button clic to use the "reduce white point". I earned 3.5 GB in free space after the upgrade. iOS tell you if you use a insecure wifi network (WPA1/WEP/TKIP). For me, PB4 are stable and safe enough to be used as your daily driver. Thanks developers and people using feedback app to submit issues and changes !