On-the-go battery booster

Any recommendations for a battery-booster?


I bought a cheap chinese one from some random phone shop before and it served ok for 6 months, gave 60-80% charge and no bigger than deck of cards.

I know mophie do cases but I just want one that plugs into the bottom for boost charge.

Anyone had a good experience with one?

I think I'll go with this:

PowerGen 5200mAh External Battery Pack High Capacity: Amazon.co.uk: Electronics

Looks like it has some pretty good reviews, let us know how it works out for you!