At this point I think it's every ViP DVR except the 622 plus the Hoppa have the capability of native 3D, meaning it's sent over HDMI as a "3D" program in the same way as a 3D Blu-Ray player. Any HD receiver, if it can display the side-by-side or top-and-bottom image on the screen without modification, is compatible because most, if not all, 3DTVs have a mode that will make it work. Heck, I can view side-by-side 3D youtube videos from my AppleTV if I press the correct buttons on the TV remote.
At this point my attitude is F-word them. As soon as I figure out what to replace Dish with and an alternative source for the stuff I have archived, I'm gone.