There was a thread somewhere on the BT forums about that. I don't think many people do; even when they get the full sync speed of 20Mb. I regularly manage 17.0Mb upload which is still pretty good (it was mainly for the upload speeds that I moved from BE).
For some reason, BT's own tests are very pessimistic on upload. The BT retail tester usually only gives a reading of 8 or so, and the BT Wholesale tester 10 to 12, even though they give more or less sensible download figures. Speedtest.net gives around 15 upload. The most reliable tester I have found is at http://mcslhr.visualware.com/myspeed/myspeed_line_ca...
which gives 17.0Mb, and I have also seen 17 to good upload sites (eg SquirrelSave). Speeds will obviously depend on the service you are uploading to, and the software used to upload. For examples, SquirrelSave's own single threaded windows application only got around 7.5Mb, but WinSCP got the full 17.
I had an issue early on where my 50Mb download dropped to 3.5Mb. Even at that time, I was still getting the full upload. Look on the BT (and other FTTC) forums and you will see plenty of moaning about DLM, which was the cause of my drop in download speed.
Moved (with trepidation) to BT Infinity 2 for upload speed. Happy BE user for several years.
Edited by StephenTodd (Mon 16-Jul-12 16:52:10)