I have got the chance of buying a second hand Comag HD Satellite Receiver PVR Ready for a very cheap price (from friend) can any one tell me if this modelis any good and is this USB idea alright?

Firstly the Comag's not a Freesat+ box. It's a generic fta box and is unlikely to give you series/accurate recording or access the 8 day freesat epg. On these type of boxes you normally only get now and next prog info