Jst to re- iterate what has already been said, Sky is as reliable as any other isp.
Prevoiusly was on Wannado which became Orange and they put the prices up. Since we already had Sky satellite tv the 2Mbps service was free, so switched over to them 3 years ago and not had a problem since.
I think the main things to consider are
1 - Use, a bit of surfing and email 2Mbps will suffice, downloading feature films youtube vids and so on you will easily need more bandwidth and so be prepared to pay extra
2 - location - how far from the exchange you are determines the max speed you can get due to the limitaions of the wires BT use. Many pple pay for 8Mbps but get far less becuse of this.
Hope it all goes well.