This item is an absolute must for a power-user of any kind, where USB charging is possible.
In my case, with an iPhone 3GS, it is even more than that.
In a 30 minute train-journey, using my phone to check email, browse the web, stream music and voice-chat with friends, I can drop anywhere from 20, to 50% of battery life with the built-in iphone battery.
Having the Trent battery helps the phone stay at top usage, for much much longer, and negates me having to take up valuable space at the other end, plugging my phone in for the required hours to charge it.
A phone should be portable, not charging 24 hours a day. With the New Trent this is achieved very easily, and means that you get to use your device for longer.
I most certainly would recommend this product to anyone in my situation that suffers from terrible battery life, or that wishes to have a portable charging solution that is cost-effective, easy-to-use, small and durable.
my only complaint as a blind person is that it is not easy, short of plugging in a device to the New Trent, to tell whether it is on or off.
What I would like to have in future models is some kind of a time-out.
If no power-drain occurs on the USB port of the battery for perhaps one minute, the battery should power down so that you can be sure you are not wasting it very slowly.
Naturally, the light on the battery does not help someone such as myself, as I physically cannot see it.
I must definitely still give this 5 out of 5 for sheer usefulness however.