I read that somewhere else (can't remember where) about 30 mins ago, there's only one problem (and the reason I don't use NTL). There is a limited transfer, and that's just... a pain. Having faster speeds will give you time to download more, so you'll reach your transfer limit . I did it on my mums PC (uses NTL) last month, luckily she didn't try accessing the internet until the month had ended :P.
Ahh that sucks it has limited time per month, i cant wait to get Verizon FIOS in my area, 50mb down and 5mb up for 200 bucks a month or 15mb down and 5mb up for 50, thats a deal if ive ever seen one