Here's a negative review and I write it in clear letters because I'm trying to help you avoiding my mistake. I bought this product after reading a number of positive comments on various forums on the internet. How ironic...
I installed the Terratec Cinergy XS on my laptop, a nice HP Compaq 6715s. Result or the operation: it works when you set it as an analog tuner, but has great difficulties with the DVB-T. I downloaded the driver updates and the software included (terratec home cinema): nothing to do.
I tried to find out what was wrong. I was thinking about an antenna problem, I found an "antenna guy" that assisted me diagnosing the quality of the digital terrestrial reception, but he didn't find any issues with it suggesting it might have been a problem with the tuner.
As a side note, when used under Linux the Terratec Cinergy will give you even worse results with choppy audio. After my bad experience I decided to buy a DIGI Avermedia Volar X at the mall: and on the same pc I immediately had a perfect digital terrestrial reception.
In conclusion the Terratec Cinergy XS HTC HD is an expensive device that doesn't work as expected and if you hear me, don't buy it.