My Hopper and HD PVR work together just fine. I've captured several HD recordings with no more issues (if any) than with my ViP 722.
However, old recordings on an EHD may be unplayable. See this thread:
http://www.dbstalk.com/showthread.php?t=203922
However, old recordings on an EHD may be unplayable. See this thread:
http://www.dbstalk.com/showthread.php?t=203922