I have the 521, with Directv HD DVR and a Samsung 50" Plasma 3d TV bought last January. (Sorry don't know the model # off top of my head)
I have the following setup:
DTV HD DVR - HDMI out --> 521 reciever DVR/BDR IN - HDMI out to TV IN.
I have the HDMI control turned on, ARC off. Picture and sound are fine. When I shut off the DVR and TV the receiver shuts off as well - GREAT!
The problems come when I turn the DVR & TV back on. Receiver does not turn on so I have to manually do that. CRAP!
Other problem is, especially if I turn the receiver on first, is the receiver constantly switches to the TV/SAT input, which I have nothing connected. Usually if I turn the TV on first, the receiver will not switch it. But not always.
I can live with the power feature, but this feature is annoying because I then have to dig out the receiver remote to switch it back (I usually use the Dir. TV remote to run the receiver).
I know I could turn off the HDMI control to fix this, however I like the feature of the volume showing on the tv. (NOt sure how that works since the on scrn menu won't display without an RCA video connector)
Thanks much for any info. And I have no other cables running other than the HDMI's just to clarify.