Hi
I have had TV Drive since just before Christmas and think it's fantastic. The difference between Sky + And TV Drive is that you can watch one channel and record on two other chanels, two different programmes. It has three tuners as opposed to Sky + Two.
You can also pause live TV and rewind it etc. It's HD ready and a bonus for me is that it has optical out and phono out for an amp/ Surround sound system. It has an 80GB (I think) and can record up to 60 hours of programmes.
It's great - well worth it. Your channel choice is different to sky in that some sky channels are not available - but I have sports and movies and don't really miss anything.
Got to the NTL website and have a good look :
http://www.telewest.co.uk/html/tvdrive/index.h tml
We kept our old Cable box and put it in the bedroom - this was the cheapest option.
Hope this helps