Bought this to use it as part of a MythTV backend system. The OS was 64bit Ubuntu 10.04 system, and it was installed without incident. The only thing to remember is that you have to install the firmware for the hardware, which has to be downloaded to the device each time the system boots.
It is more complicated to set up a DVB-S system, compared to DVB-T as you have to mess around with Diseq settings (to do with polarisation of the LNB), but thankfully I had a knowledgeable friend (Hi Ken!) to help me.
I still have a lot to learn about Myth, but I can now record programs easily, so that is half the battle :-)
It is probably much easier to set up this card under Windows, but it was done in an evening or two with Linux (and I was busy doing other things, and not just Linux on both those evenings!!)