I have been using Telewest Broadband for several years now and can say (touching lots of wood, fingers crossed, etc :cheesy: ) that I have found the service very reliable. So much so, in fact that if I ever moved house I would want to go to a Telewest area.
I have recently gone to 1MB from 512KB but am not sure how much extra benefit the extra £10 pm is giving me. Accessing pages still seems to take the same time, however, once found the site is displayed immediatley. File download speeds are obviously quicker, assuming the site supports the higher bandwidth.
I think I can safely say that placing trades and executing them is no quicker.
I worked for Telewest broadband support for 6 months and the 2Mb service is just as reliable as all the other services. You are not realistically going to get transfer speeds of 240K per second because there are not that many sites out there with that much bandwidth - what it will help with however is simultaneous downloads (Kazaa Lite - IRC - Newsgroups) - Itll be perfectly possible to have 4 downloads all going on at the same time at 50Kbps