I have an OEM and two generics for the OV, and an Anker and two OEM for the Evo, plus an External Energizer battery/charger.
The generic OV batteries aren't great, but as emergency backups they are nice, as is the charger, especially for the price. The external is handy, especially since it can work on anything, but once I got the Anker battery, I passed it on to my mom for her Blackberry.
The Anker battery ROCKS. It's rated at 200mah more than stock (OV ones are only 100), but gets about 20% more life, I keep an OEM handy for spare on long jobs, but rarely need them now. I hate thick phones so this was the way I preferred to go.
The Anker charger is great in some ways, bad in others. Bad because while it's universal, it's kind of a pain how they did it. It's fantastic though since it can work off USB, or plug into a wall. It even has a USB out port for charging through there as well. It's pretty of slick actually. If only it was a little easier to connect a battery to it would be perfect.
I will back up Xrae on their service, I got mine fast as well, and like I said, I like the product, I will buy from them before another oem or generic at this point. The price is good as is the service. Sorry, I know it sounds like a commercial, but really, it's good stuff at good prices.