Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Could be better

I bought this battery to replace a spare battery for my canon 40D. it performs well and charges without any issues. but it doesnt hold as much of a charge as my oem canon battery. from what i notice, i can probably get about 500 shots off one charge. i feel like it self discharges very quickly too. i can leave my canon battery in the body for a week without seeing much loss of charge, but this battery seems to suffer more in the same scenario. either way, it makes a very good spare.REVISE:I don't think this battery is reliable anymore. There looks to be some "charring" on the bottom the surface of the battery, possibly burn marks from over heating. Was worth the few months of use, but would not recommend because of possible damages to your camera.