Just came back from a phototrip. My original Canon LP-E6 worked well for my 5DMkII. Could read the exact shutter count for each battery and also the amount left. My 3rd party batteries, though no questions, have been great workers soldiering on, but seems to die off faster in the cold and what is more, cannot be made to display how much left because of a lack of a chip in them. Note- this phenomenon is only unique to 5DMkII.
Finally I touched down, ran straight away to TCW and bought not one but two LP-E6 cos I foresee myself going to some cold, zero or sub-zero region.
So from now on, for my Canon 5DMkII, it will be original battery.
My 50D leh? Still usng third party battery lah...