I've had my Droid 4 since October 2011, and have had no significant problem since that last OS upgrade. Yikes. The key problem was the Email. All of a sudden I had about 1,500 old Emails (2-3 years old) in my IN folder. So I took it back to the Verizon store and they suggested replacing the stock mail client with K-9, a no charge alternative Email program. So we loaded that and I spent the evening configuring it to my POP3 email account. I've got it set to poll the mail server every 5 minutes, and I've had no noticeable battery drain. I'm once again please with my Droid 4 purchase. I'm looking forward to the "fix" release -- hope it comes sone. Good luck with your device!
