I use the HD621 with my HDI Dune BD Prime Blu-Ray backup (NAS) player. I can only attest to the wonderful soundquality I'm getting from my system now with the HD621. Playing 6*24/96 recordings or even regular 6*16/48 is wonderful. I especially like that I can really crank up the volume and not hearing any distorsion from good recordings. Everything is crystal clear with wonderful fidelity!
This is just what our Meridian setups have longed for since the day DVD-A was invented. And now with the help of Blu-Ray and the HD621 we are getting it

Tip: Configure all vertical speakers as large if DSP5k or larger. I also like to run without a sub in my setup and let all large speakers handle and distribute the LFE channel. It really widens the experience with more
even bass response throughout the room as well as impact when needed.