The off-board charger from Intenso is really great! with its 10,400 mAh it keeps almost forever, at least for Mobile Phones. Through its 2 USB ports (1x + 1x 1.0A 2.1A) allows even charging two devices simultaneously. By means of the supplied, commercial smartphone cable, which is however turned out a bit short for my needs, simply invites you to an external battery again (eg. Via outlet adapter or simply on the PC).
Benefits: + Large capacity + 2 USB ports + (Not tested) also compatible with iPhone (requires additional cable, not included
Disadvantages: - USB cable is possibly somewhat short - Desirable would be a 2. USB charging cable if already 2 USB ports are present
All in all, I recommend this external charger without a guilty conscience! :)