This card is a low-profile card that can readily be used in place of the pcHDTV card (wherever that card is deployed). And, the good news is that its about $40 cheaper.
The drivers for the card are the DVB drivers, which are built in to all later releases of the kernel that are used for Mythbuntu. Setup is quite simple. You should always set up the HD 800i capture cards as DVB cards. The choices listed on the setup page will include one that says "DVB", and that's the one you should choose.
For the HD 800i cards, a couple of options that you will probably want to use are:
Recording Options
Max Recordings: 1
Open DVB Card on demand: (check)
If you are getting your guide data via EIT, you might want to enable it for the HD 800i encoder. To do so, check the EIT box:
Use DVB card for active EIT scan: (check)