For batteries so stunningly cheap I did not expect them to be any good, but for the money they are excellent. There is not a lot of difference in running time between these and the Canons' (that I have noticed) so for he cash you can grab a load to use as spares. (I have about 4)
I have used them trekking(eg a couple of weeks away from any power sources to recharge) They seem to cope fine with sand, snow and extreme temperatures of alaska after midnight. (Northern Lights are stunning there but minus 20 degrees C) They also seem to keep their charge if left unused for a few weeks.