I decided on the RichardSolo Battery. I placed my order. It won't ship til near the end of the month but I did more research and here's what sold me:
RichardSolo is the only one that lets you charge the iPhone and the Backup Battery together. The Mophie requires you to charge it separately, and the 3G doesn't have a chance to charge them together because they stupidly put the mini usb port right next to the Apple pin, so that if you connect it to the iPhone there is no way to charge it.
And neither of them give you a USB wall charger, which is probably 8 times faster than charging from your computer USB port...
RichardSolo does and that's a PLUS that nobody seems to realize until you start having to depend on these little boogers... Boy I'm glad I researched these.
