I don't use sky DSL but I have in the past used OpenSky which is offered by Eutelsat.
I depends why you are considering this rather than ADSL over copper. I used OpenSky because I couldn't have ADSL. It is then a viable (if expensive) option as you either use a standard dial up ISP or (the very expensive) two way communication DSL. The latter needs £2k of equipment and costs £100/month.
Limitations are very restricted download volume at high speed and very slow 'best effort' once you are over the limit - no faster than dial up. You need to be connected by phone to make the download work so you pay twice - unless you buy the two way system.
Interesting features include emails without connection (they are sent from the satellite to you when they arrive but your PC has to be 'on'), FileFetch which offers downloads of favourite 'files' which you can select offline. Some TV available.
As soon as I could have ADSL over copper I switched - it's just a better deal.