I had an old Sky system - 10 years old which kept asking me to replace the viewing card. I wanted to update the system to get HD channels so I bought the Humax.
I unscrewed the coax connector at the back of the Sky box and connected it up to the Humax. Following the on screen instructions I was up and running in about 10 minutes. Nine minutes was installing the latest software (automatically).
My old Sky dish only has 1 cable (single LNB). If you want to watch 1 channel and record at the same time, you will need to update the LNB. You need to be careful which LNB you buy if you plan to do this (it needs to match the dish shape). Other than that, making a cup of tea is probably as difficult.