It depends on a whole raft of factors, including how busy your local exchange is.
We have MaxADSL up in the Norfolk cottage. It's 50 yards or so from the exchange, and there are not many folks in the village with ADSL. It connects at 8 mbps (no surprise) and I normally get speed test results around 5.5mbps, sometimes a bit more. I've never noticed it slowing down in the evenings, either!
Now in Essex...