Review: iPhone 3G
The biggest advantages of the 3G iPhone are its 3G-ness and GPS. When you're covered by AT&T's 3G signal, the iPhone will browse the mobile web much faster. It is as fast as other 3G phones when it comes to downloading and opening web pages, but we found the finger navigation to speed up the browsing process.
As for the GPS, it works well, and can map out very accurate directions. The 3G iPhone does not offer turn-by-turn directions right now, but I've read that application developers are already working on them. Once these apps are available, the 3G iPhone will be on par with a lot of other cell phones that offer GPS.
The Apps store is a great new feature to have, but exiting first-generation iPhones also have access to the Apps Store with the 2.0 firmware upgrade. If you're an existing iPhone owner and really want to have the 3G and GPS chips, this new device is probably worth the price. If you don't have access to AT&T's 3G signal, then it is probably not worth running out and buying.
But that's not to take away from all the things the 3G iPhone does well. The UI is as great as the original's, it is a fun device to use, it syncs your content easily with iTunes, and it is a better phone than the original.