I am on BT Unlimited Broadband (WBC) with a download sync of 7.7 Meg but usually it's 11 Meg. A few months ago the noise margin increased to 15 dB but I didn't care as it was still plenty fast enough. The quiet line test is completely silent so it's unlikely to be a line fault. I asked about fixing it recently and presumably I have fixed the problem so maybe it'll drop back to 6 dB eventually.
The other options on my exchange besides WBC are C&W, AOL, Tiscali and TalkTalk. Fibre is in my exchange but it's only available to those very close and isn't likely to reach my area for quite some time.
I would prefer unlimited usage so I don't have to monitor it and I don't mind paying extra and I am also fine with P2P etc slowing down during peak times.
I would also prefer the broadband supplier also take over the phone line and I pay the line rental to them so I only get one bill.
I am not tied into a contract with BT and have been paying £29.40 for broadband with BT for a number of years.
Also not really thinking of switching to a business product but might if it makes sense to do so.
My first thought was Xilo LLU using the C&W network but only because it's the only C&W reseller i know much about although I don't know if they take over the line.