I have a brand-new, unrooted Sprint Samsung Galaxy S4.
Just spent 25 minutes on the phone with sprint tech support (866-518-0927) and spoke to a nice lady about these issues with the MF9 update. In particular, my issues are as follows:
Received the update around July 18
Problems
Started experiencing significant BATTERY DRAIN on July 19 or so, with a complete change in battery usage profile. Google services and android core apps began to dominate, while screen usage dropped. Today, for example, my battery life is down to 17% after LESS THAN 6 HOURS of use. Screen has been on for less than 2 hours, and I was sleeping for part of this time. I have not made any phone calls, listened to any music, played any games, or taken any pictures. I watched one youtube video and updated a couple of apps. My biggest offenders: Android Core Apps (47%), Screen (25%), and Google Services (15%). Everything else is minimal.
Phone is tremendously OVERHEATING. I know it's hot in death valley, but it's pretty hot in my pants too -- feel like I can cook an egg in there (battery temp has reached 37 C)
Gallery app takes longer to open (I have a galaxy s3 that I have not yet sold connected to my wifi network, which opens the app faster). Also, I no longer have trash icon in gallery app.
Lost the black notification bar on top of home screen - now underlying background is visible (this is not necessarily a problem).
Phone is tremendously overheating and processor is constantly running. Have I already mentioned this?
When I long-press the home button, one process ALWAYS shows up: com.sec.app.MIPErrorNotifier and does not go away.
Attempted Fixes
Found a few "fixes" in various forums (sprint, google, etc), which I have utilized with little success.
Disabled Google Play services, which, for some, has apparently been chewing through the battery due to an issue with google maps. Incidentally, this renders Google Now and Google Hangouts essentially worthless.
Uninstalled Google Maps update and reverted to factory installed version (6.14.3?)
Have disconnected and reconnected my phone with my Google account 3 times.
Have rebooted phone multiple times.
Have removed battery twice.
Disabled Sync (was previously syncing my gmail and other Google services as push without problems)
Left Power Save mode enabled. This has been on since I purchased my phone based on battery-saving tips that nearly every website recommends
Left GPS, bluetooth, and all "Smart" Samsung features OFF (occasionally used smart stay previously, but disabled with these problems)
Downloaded JuiceDefender and Battery usage app to assist with battery life, but to no avail. I also downloaded AVG Antivirus to combat any virus threats (battery problems occurred prior to downloading this app)
I did NOT mess with the DRM settings, as I was uncomfortable doing this.
Sprint conversation
The lady I spoke to grabbed a sample S4 from her office and began tinkering with it as well. I told her my battery usage stats (android core, google services, etc.). She stated that not everyone in her office with an s4 has experienced these same issues, but made it sound like some may have (didn't directly state this). I asked her if there were known issues with the MF9 update and referred her to the numerous threads in the sprint forums regarding this issue to show that this is not an isolated problem, and she said that nothing has been formally documented that she could see. Her suspicion was that there may be some faulty software integration between the MF9 update and google services, and RECOMMENDED THAT I FACTORY RESET MY PHONE. She also noted that there is NO WAY TO UNINSTALL OR ROLL BACK THE UPDATE, even after factory reset.
I will factory reset my phone later this afternoon, and if my battery problems persist, will have to to go to the sprint store to see if they can do anything. She indicated that they may know of some way to roll back the update, although why some local dude would have an answer to this problem while she does not is unlikely. As an aside, my battery life has decreased from 17% to 11% in the course of writing this post. Awesome.
Please call tech support and badger them with this issue. Perhaps with our powers combined, they will hasten to release an update.