Good accessories, unfortunately prone

I use the iPhone 3G very intensive and that a charge lasts less than 4 hours is not uncommon. For this reason I have decided zuzulegen a separate battery. After bad experiences which I have made with cheap batteries designed for other mobile phone, my choice has fallen targeted on a name manufacturers. Especially for the reason that I wanted a battery which not a few months by memory effect and low quality becomes unusable.
For Philips Battery I can go over 1,5Jahren say that the batteries have a weak point and that is the elastic connecting piece between the iPhone and the battery Schnitstelle element. After a few months went repeatedly to loose contacts. Another problem that I had with the battery is that at some point the iPhone was no longer loaded, unless you have the battery itself connected to the PC / outlet.
Another shortcoming is the depth of the battery. The iPhone is thus (significantly) more than twice as thick. This fits in your pocket more difficult by the fact that the battery can slip. Moreover, I suspect that my wearing of mittlerweilen 3 batteries due is that it bends through the transport in the rear back pocket and thus the loose contact occurs.

Nevertheless, I'll get myself a new day again. I had no memory effect so far, but the significant depth of the battery is for me not decisively, the resulting defects are covered under warranty and I know so far no better product.

--update 17.03.2012--

Meanwhile, I have a better product for me gefunden.System-S External battery pack battery / backup for Apple iPhone Classic and 3G
in conjunction with Sanyo eneloop battery Mignon / AA HR 3UTG 2000mAh 8er Bonus Pack (8 + 2 Batteries Battery boxes)

Pro:
- Robust
- Flexible because it is powered by standard batteries
- Higher capacity
- Works with iPhone 4 / 4s

Cons:
- Bigger battery part
- Transport in your pocket only conditionally possible