Unhappy [Q] Auto Reboot & Continuous SYNC after sense 6.0 update

Phone: HTC One
Carrier: AT&T

Never rooted/unlocked.

After update to sense 6.0,

1. Phone auto reboots every 6 hrs once (while on battery or on charger).
2. Battery drains in 4 to 5 hrs and phone becomes very hot.
3. SYNC is continuously ON most of the day, around 1.5gb of mobile data is consumed per day (Google Play Store, com.htc.sense.uid.socialplugins.shared:10018 & removed apps use max data).
4. When the SYNC is ON, device will be very slow ( about 30 seconds to 1 minute later the notification disappears after reading the mail/message/missed call).
5. Apps requiring update from play store, keeps getting re-installed several times when the SYNC is ON.
6. When the SYNC is ON, text messages will not get delivered, they just keep waiting for 2 to 3 minutes.
7. When the SYNC is ON, the Alarm doesn't work.
8. Some times power button will not respond or too slow to wakeup the screen, sometimes device reboots if I press the power button multiple times.

Factory reset for 3 times.

If I leave at default apps, device is OK. But once I reinstall all my apps from play store and setup (individual app manually, with out restoring from backup) the problems reappear.

Please HELP..