Recommendations for a battery on a LR EGO atty? Will this one work?

[blackjackel]

I think I'm going for LR EGo, wanted to know if this battery would be ok:

Joye eGo XL 900mah Battery

its 900mah, 300 more than the default EGO battery, would this crap out on me? What kind of MAH or voltage ratings minimum are we looking at for something that wont promptly die on me?

Any recommendations for websites that sell parts for cheap?