Hi, Glenn54! I have owned the Marantz DP-870 for many years (I think it was one of the first outboard decoders available). I have not used it for some time as I upgraded to a HT receiver a few years ago and took the unit out of the loop as it was not needed. I also bought the 950/770 in December of last year.

I have not heard the Acuras amps. But I can tell you that to my ears, the 950's perfpormance in DD runs rings around the trusty but aging Marantz. Just having the additional options for surround is great, and I have never heard DD like this before (not sure how much relative contributions to this conclusion are made by the 950 and the 770, but the resulta are superb). I have made no A-B tests, of course, and this is a subjective opinion. But I opted for the 950 and the 770 over some considerably more expensive gear, and think I made not only the right choice, but an outstanding choice.

Good luck!

Mike