I don't know if it helps but just for curiousity, I did a speed test on my Three dongle, the results are 10mbps download and 2.39mbps upload. In other words, 2.3x as fast as ADSL on the upload.
So if you have a particular application that needs good upload speeds, and ADSL isn't doing it for you....???
So if you have a particular application that needs good upload speeds, and ADSL isn't doing it for you....???