Can't really add much. I had mine installed last week. If you have a HD TV - make sure you get the engineer to set it up before he goes as I understand that you can lose the picture and then it's very tricky to rectify.
You'll also get all your subscribed channels on your other box so don't worry.
Pretty much everything is free - TV Choice n Demand is free for another 2.5 months and there's plenty to watch in there. TV Catch is also free. You only have to pay for the VOD films and the VOD music.
Thats about it - scheduling a recording - press 'home' find your prog in the TV guide, press record (or yellow to record a series) and thats it!
You only really need 2 buttons - 'V+' and 'Home'