As for being disconnected by Sky, I was reading the story that one link goes to, but it seems that a mistake was made and the person was cut off for the wrong reason.
Personally when I joined I wanted to get a similar speed to what I had with my previous ISP. They maxed me at 17.1Mb/s with 1.3Mb/s up stream with annex A or 15.4/2.3 with annex M. I admitted that everything should have been capable of getting this as I was using the same router (my own).
Sadly she couldn't get me the speed improvement, but I certainly wasn't cut off.
The router I use is WiFi n enabled, hence my argument that it too is better than the Sky router.
Provided that you keep the Sky router, in case of an issue and to keep the login details unique to you, there should be no issue as far as I'm concerned.
If Sky were to argue that I should use their router, which is a lower spec, I am sure I could find a friendly barrister to argue that they were enforcing a set of unfair terms and conditions. My line is one that only goes to my home, the router signs into their servers, the router doesn't cause any spurious issues and my account is paid up to date.