What do you want to know? I've had the 600k service for quite a while now, and while it works it's great, but when it's broken the customer service is crap. (But that's true of most utilities these days, isn't it?) Oh, except that their news servers are crap, so you want to get yourself a news service elsewhere; and I can't comment on their email service because I don't use it.
Do you really need 1M? I have found 600k slowish only once, when I was running some fairly heavy networking applications that were really designed for a LAN over the cable through a VPN tunnel. I'd have thought the only other "need" for 1M would be wanting to download large quantities of porno movies. Most of the time you're running at way below your connection speed because there's some other bottleneck between you and the server you're talking to.
Actually a recent improvement in their Ts&Cs is that you can now take the cable modem service without having to buy the TV service - they used to be bundled, so we used to have to pay for a TV service that we never used as we don't have a licence.
For more techie detailes of using cable modem services than you're likely to need see Robin Walker's web site (Google for "robin walker cable modem" usually finds it, I never bother to remember the URL.)