I've had virgin broadband for about the last 12 or 13 years, and generally since moving (10 years ago) we've gotten close to the speed that is on our package when ever I've checked, normally in the evening when the load is higher so have been happy with that.
A few weeks ago we got a "free" upgrade from 100mgb to 150mgb and we have slowed down.
The past week it has been noticeable the time taken to load some pages, so on Saturday I ran a few speed tests (several different sites to get an fairer view) and it returned a download of between 25-33mgb. and an upload of 6-8mgb. Re ran it just now and its still between 30-42mgb download and 6-8mgb upload.
So I've got 50% greater potential delivering 50% slower, wonderful.