This is about the only PC TV tuner on sale in the UK which supports DVB-T2, which is required for receiving the Freeview HD channels. I purchased this for my MythTV system after reading that drivers had been written and intially I had to compile and install them myself, but from Linux kernel 3.0 they are included (I am using Ubuntu 11.10 which has support for this tuner built in).
This is an excellent piece of kit for MythTV, it gets a better reception than my exisiting Nova-T 500
card and is more convenient as it is USB rather than PCI (more modern motherboards have phased out the PCI slot in favour of a PCIe one), so it is easier to upgrade a motherboard without worrying which slots are on it. The only downside is that it's only a single tuner, but in MythTV you can create multiple virtual tuners to record more than one TV channel from a single tuner (as long as the channels are on the same multiplex). At the moment I am using this in tandem with my Nova-T 500 card to have a total of 6 tuners, but ultimately I intend to replace the Nova-T with another one of these, probably about the time I'll be looking for a more powerful mini-ITX motherboard.
If you are looking to add Freeview HD channels to your MythTV set-up then this is about the only choice you have, at the moment, and if you are using a Linux kernel > 3.0 or don't mind compiling your own drivers for it then it practically works 'out of the box' in as much as anything under Linux works 'out of the box'.