I have a Motorola Droid X and I've been using the 3G Wi-Fi mobile hotspot feature so that I can get online with my laptop and my iPad. In the past, I used to tether using the USB cable.
Well, I did a speed test because I was convinced that 3G Wi-Fi Mobile Hotspot was slower than USB tethering. Sure enough, with 3G Wi-Fi Mobile Hotspot, I was experiencing download speeds of 0.5 Mbps. With USB tethering, the speeds were almost 3x faster! 1.3 Mbps.
Are you experiencing similar results?