Here's my post that DodgerKing was referring to for a video of my HR20-700 in action.
http://www.satelliteguys.us/1638355-post92.html
As far as the H20-600 goes, I had one for about 2 years without any trouble, no overheating or otherwise. Now I may not have had the same over heating trouble others did because my H20-600 wasn't in a cabinet. It was in open space where it had plenty of room for the heat to dissipate. But I'm not going to say the boxes were perfect just because I didn't have trouble because I did read about a lot of problems that people did have.
Anyway the H20-600 had the best OTA tuner in any of the D* boxes I've ever had. Which also may have led to the over heating because it had an OTA tuner chip that none of the other D* boxes had. I've heard that the OTA tuner in the H20-100 isn't as good as the one in the H20-600.