I wanted a backup battery for my phone as I didn't like carrying around usb cable. I wasn't sure how good a cheap third party battery would be but decided to risk it anyway as other reviewers were happy with product.
I wanted to wait and see how the battery performed before posting a review, I've been using it for 5 months alternating it's use with the original HTC battery and would say that it is on par with it. It doesn't last that much longer that the HTC one but than I wasn't really expecting it to considering the price.
I would recommend getting a backup battery for any smartphone and I have found the Anker battery serves very well. I found the delivery service very good(ordered on the Wednesday and arrived on the Saturday)and have nothing negative to say about seller (LaptopMateUK).