I was a little dubious about buying a non-Canon accessory for my Canon S95 camera, but my worry was groundless.
I was due to attend a 4 day Music Festival, and decided to give the battery a test drive to see how it would perform. I fully charged it before I left, and off I went. Throughout the 4 days, I took 170 x 12MB pictures and 17 x HD Movies. And the battery still had juice left in it when I got home! Seriously impressive.
In fact, not only does the battery match the duration of the standard Canon battery, I would even go as far to say, it may have even out-performed it. But bear in mind that you have to fully charge the battery a couple of times before you reach full capacity.