Sky is excellent, but not all exchanges offer the Sky Max service, which is the £10 a month up to 16M speed and
no download limits, or the £5 a month Mid service. You need to be a Sky TV subscriber to get these.
If you're not sure whether your exchange is Sky enabled, go to
http://www.samknows.com and choose "Exchange Search" and type your exchange name or town in. Then look at the part which says "LLU Operator Presence", and look for a green tick beside Sky / Easynet.