Viper Lair posted a review on the OnAir USB HDTV-GT Mobile ATSC/QAM TV Tuner

Unlike satellite or cable HD, OTA HD is fully uncompressed. What this means is the picture quality should be better than subscription based HD. The downside of uncompressed HD is that if you have plans of recording this type of video, be prepared to have a lot of disk space used. the included OnAir software, a mere 10 second capture used up 25MB of disk space, 30 seconds eating up 57.3MB. For a 60 minute show, you'll probably use up about 9GB of space. However, the picture quality is simply amazing. Let's just say with LOST premiering tomorrow night, it's going to be quite an experience.

OnAir USB HDTV-GT Mobile ATSC/QAM TV Tuner Review