Aaron reviews the HTC Radar 4G, T-Mobile's first 4G Windows Phone and a well-built mid-range device.  Available now for $99.99 with a new agreement, Radar 4G offers a 1 GHz Snapdragon CPU, 3.8-inch display, 5-megapixel shooter with 720p HD video recording capabilities, a front-facing camera, and Windows Phone 7.5 (Mango).  Is it the phone to get this holiday season, or should you hold off for a different Windows Phone?  We'll figure it out.  Part 2 of 2.