I only get 4480 on that speed checker, whereas I just got 9700+ on
http://www.speedtest.bbmax.co.uk/
They can't both be right, which suggests that broadbandspeedchecker doesn't have the capacity to reliably serve tests at higher speeds.
People ask if their speed is good or bad. Why bother? Whether your speed is good will depend on what you're paying and what that service is advertised as. If it's advertised as 20meg and you get 4meg, well, that's not good is it? If it's advertised as "up to 8meg" and you get 6, well then it's not too bad. Then there's whether or not it feels fast enough for you, personally, as an internet user. If not, then it's not good enough, if it does, then it is.
There isn't a yes or no answer.