From all the reading I've done on the 875, definitely stay away. It works GREAT for some users, but there is a problem specifically with the setup you have (the DirecTV HD-DVR). Multiple users have reported that every time you pause, FF, RW, etc. a broadcast running Dolby Digital, you get a 5-10 second audio drop out (every time!).
I was set on the Onkyo for the same reasons (video upscaling), until I read all about the problems with the DirecTV box... Since then I'm totally sold on the 3808ci (thanks to some pointers from the folks on these boards). The Ethernet connection and awesome GUI were more than enough to impress compared to imagining trying to explain to my wife why my new $1000 Onkyo receiver causes the volume to mute every time you do anything with the DirecTV box!
