i get a pretty constant 18mb offpeak with O2, only drops to 10mb during the busiest times, and cos i'm a mobile customer I get it for under a tenner.
Theyre definiately one of the best ISP's ive been with, but theyre gettin more n more well known now so soon be getting slower and oversubscribed...
I think the next 12 months will be the decider. If they keep up with demand and upgrade their hardware to cope they're worth signing up with. Else they'll soon not be any different to any other ISP.
EDIT:
Not bad for 8pm in a busy residential area just outside of Sheffield.
N this was my best result yet.