I saw "I don't want to pay $100 for a battery" from someone, in a $1700 camera? I don't get it . . . get your camera at the best price possible, then you can afford genuine accessories.
Are there any improvements that come with these batteries, or is it all a price game?
Do any of these, for example:
take more of a charge?
last longer (more charge cycles)?
operate in more extreme temperatures?
This brings up an EXCELLENT POINT. Everyone is focused on cheap alternative batteries. The other side of the coin is a battery built to be superior to the Canon OEM. This isn't as common but what if someone offered a better, lighter, stronger, faster and more colorful battery than Canon (with a big 'S' on the side)? If it helped me and improved my use, I would want to buy it, even if it cost more than the OEM. It would suck to have the best most ultimatest and badasstical battery around and not be able to see any charge status or have it talk to my camera correctly. So yet again, thanks Canon for making things more complicated that don't need to be.