I know that T-mobile uses 1700MHz for the 3G uplink and 2100 for the downlink. I saw that the 3G frequencies for the X10 Mini do not include the 1700 band but do include the 2100 band. Furthermore, I saw that the exact range of frequencies (from the phone's specs and from Wikipedia about the frequencies used by T-mobile) that the phone uses are contained within the band of frequencies used by T-mobile for the downlink. (I can tolerate the slower Edge uplink but I must have the 3G downlink connection because I use Android's hotspot feature to connect with my laptop.) So I contacted a seller who (of course) said it would work. Then I contacted Sony/Ericsson and the person who, after my explanation of my research (as above) replied with a quick answer saying something like "then it should work". That didn't sound very confident, not enough for me to buy it. I know that the Mini can be used on T-Mobile to make calls and even to make a data connection. But my question is: Has anyone tested if the Mini on T-mobile will CONNECT AT 3G FOR THE DOWNLINK/DOWNLOAD SIDE? Running the "Speed Test" app would remove all doubt. If anybody out there has one and is using it on T-mobile U.S. and would run SpeedTest on it (or has otherwise tested the download speed), I would love to know the results. Thanks very much for your help.