What are peoples thoughts/experience with the Quark Mini CR2?

I couldn't resist picking one up from 4Sevens for only $28 with CPF discount. It appears very small. Not keen on the battery type, as I have no experience with it. I was actually wanting a single AA model, but it was out of stock, and the price/size of the CR2 model got the better of me. I'd be especially interested in hearing about actual runtimes. I've posted on EDC forums concerning this purchase, and the responses I've got have been positive. Thanks for any feedback. My only experience with LED lights is a Fenix P1D, a couple of E01' and E05'.