The new T-Mobile ( DT) G-1 smartphone -- the first device that uses Google's ( GOOG) Android operating system -- is quite good. However, Apple's ( AAPL)iPhone 3G is still king despite some very clever and innovative features in the G-1. The G-1, a mid-sized phone made by HTC, is what I call a slider phone because the screen pivots out of the way so that you can use a QWERTY keyboard. Overall, it measures 4.6 by 2.2 by 0.6 inches and weighs 5.6 ounces. The screen measures 3.2 inches diagonally. The phone is loaded with terrific features, including an autofocus 3 MP camera, Wi-Fi, Bluetooth, full-screen Web browsing, Google mail, Google Calendar and Google Maps. The phone also provides rapid access to the new Google Marketplace -- just like Apple's App Store -- except that it offers far fewer titles. I found one or two titles which come in versions for the G-1 and the iPhone - such as "Pro Football," which look and operate remarkably similar in both formats. The G-1 runs on an operating system called Android, an "open-source" Linux-based system. Open source means that anyone including the manufacturer and end user can use the software and make changes to improve it. It's different from OS X, Microsoft ( MSFT) Windows in that any improvements that are made have to be shared with everyone else -- for free. The G-1 has a touch screen. When the slide is hidden, the screen is read vertically. It flips to horizontal when the keyboard is revealed. All in all, it works very well but I wish the keys were a little more responsive to my touch. They seem a little stiff.