Sometimes it's hard to tell that you just have a bad phone. You stuck in there and now finally your patience is paying off. I'm so glad to hear this as I remember your story. I'll bet with a few tweaks or disabling of some apps it will get you slightly better numbers if you try.
I'm starting to wonder if there is some hardware issue with the first units, specifically the wifi antenna. My first S6 was the wrong memory config, but I was told to activate it until the 128gb unit arrived. That one got 2-3h hours SOT and wifi would use over 50% of the battery sometimes, with the screen using way less. The second one had blotches under the screen, so I had to warranty exchange it. That also got 2-3 hours SOT with the same lopsided wifi battery usage. My third one gets 4 hours SOT average, but on weekends when the email is set to sync every hour instead of live, it's closer to 6 hours. Screen to wifi battery ratio is normal. The current S6 does not report the Sony sensor, which indicates it's of newer manufacture. Also consider that most of the severe battery issues happened with the TMo units, which were released earlier than the other carriers, presumably because they received their stock first.
Also, this is anecdotal, but I was talking to a buddy of mine during my drive home. With the S5, I would sometimes get disconnected in this one intersection, but it was rare. With the second S6, I got disconnected 4 times and I wasn't even halfway home. Yesterday I got from door to door without any problems.