The results have been pretty good. I consider myself a light user. When I'm at work and I don't have access to my phone I turn wifi and data completely off. I only use data when I have my phone physically on me and I'm out and about. If I'm at home I'll turn data off and keep wifi on. I don't let the phone auto-switch to which antenna to use because it just uses battery (and as well know the phone sucks battery) constantly scanning for those signals.
There's barely any difference in size with the extended battery and cover. It feels a little more beefy in the hand, but I still love holding the phone.
Also if you're curious what ROM I'm using, I'm using CM10.1.3 (4.2.2). I used 4.4.4 CM11 for a long time and the battery life on that just sucks really bad. Also the performance takes a hit. I decided to downgrade to the last official Android version that's been released for this phone and it's pretty smooth with conservative battery use.
This is what I bought: http://www.amazon.com/Samsung-ETC-I5...attery+verizon
Anyway here are the results of medium use through the day...