When I updated to 4.3, it introduced all kinds of problems with my SIII. Power drain (2x faster than 4.2), camera intermittently deciding it didn't work, etc. I hoped 4.4 would fix these. The power drain is still there, and now there is an even bigger problem!
When I first updated to 4.4, it got stuck in a restart loop. Eventually I managed to get it updated and running, but now it still shuts down randomly on occasion. Sometimes after is shuts down (and may or may not loop), I get a message "Device memory damaged: The data partition has been corrupted. You need to reset your device to factory defaults. This will erase all your data." Thanks Verizon for making a good phone bad, and then even worse in the 18 months I owned it. Thankfully T-Mobile will now let us check coverage in our area with a borrowed phone, because if Verizon can't fix this, I am not sure I see any reason to stick with you.