I have used it in testing and it worked okay. I was careful not to abuse it. Biggest issue is that after a short while your hands cramp up! Far as I know, there's no heavier duty option that size or close. Other options are all too big, IMHO. The new Eton BoostTurbine 2000 http://www.etoncorp.com/product_card/?p_ProductDbId=1869045 looks promising, not too big, battery for an initial charge and storage, but isn't yet available to test. I have asked for a sample when they start shipping, but...

The Eaton Boost Turbine 2000 definitely looks promising. I will look forward to your review. I checked the specs and looks like a 1 amp output at 5 volts which should make most smartphones happy, but would not get into the tablet range.