3 variations
I use 3 mobile broadband when the wired alternative goes AWOL.
Speed on 3 varies between dial-up and near-wired-broadband speed. As a guide, the current wired broadband speeds are 872Kbps download, 187Kbps upload.
I have logged 3 speeds of 656Kbps download, 86Kbps upload.
For some reason, the 3 signal strength varies a lot. Four bars can change to 0 and connection loss. I do get HSDPA, but that frequently changes to '3G', without any apparent reason (e.g. weak signal?)
Re. contention - as 3 goes via mobile phone masts, do phone users affect 3 broadband?