I got 2 of the verizon batteries (and two more later) and they work VERY well.
but it really started to annoy me how much thicker it was. not so much in my pocket (no big deal) but it meant all my cradles no longer worked. that was really getting annoying.
SO I wanted to go back to the thin battery and I found a viable compromise between the stock batter and the thick extended battery.
I got a couple ChiChiTech 1900mah (real ones not the fakes) batteries that fit behind the STOCK casing IE not thicker.
they work WONDERFULLY. not quite as long a life as the extended battery (its 150mah short of that but still 400mah more than the stock battery) but really darned close. more than close enough for me.
I easily get through a full day even of really heavy usage without a problem.
I did 2.5 hours of GPS and otherwise decent usage and still have 50% on the battery when I plugged it in at night.
Very impressed. so if you want more power but not thicker order a chichitech battery. I got 2 batteries and an external charger (a nice one actually) for $35 on amazon.
Just make sure its the "real deal" and not a fake (there are a lot of chichitech fakes floating around) on amazon their seller name IS chichitech.
Amazon.com: CHICHITEC Sprint HTC EVO 4G 2x1900 mAh Battery Slim Design Longer life than OEM+Wall Travel Dock USB Charger also for EVO Shift 4G,Verizon Droid Incredible 2, Touch Pro2, myTouch Slide, Google DesireZ, G2 by CHICHITEC ONLY BEWARE KNOCKOFF
They also have just a single battery for $18 if you add something else to get over $25 it ships free.
Good deal. I am very pleased with them.