The good: it offers new features including support for high-speed 3G networks, third-party applications, and expanded e-mail. Its call quality is improved & continues to deliver an excellent music & video experience.
The bad: lack basic features that are available on the simplest cell phone(Bluetooth connectivity). Battery life not good, and the 3G connection tended to be shaky. Also, the e-mail syncing has its faults.
The bottom line: The iPhone 3G adds features and sharper call quality.The 3G support is good. Critical features still are missing, and the battery depletes quickly under heavy use, but the iPhone 3G is a big improvement over the original model.