What level of Dynamic Volume did you use?
I just finished watching "Live Free or Die Hard" from a recording on the HR21. It's late enough that I used Dynamic Volume on the "Midnight" setting. It seemed to work slightly better when the volume peaks were low to moderate. With high peaks, mostly the big explosion scenes, it did sound a little muffled. I tried reducing the DV level to "Evening" and "Day". This seemed to eliminate the slightly muffled sound, but it made the volume range too great, that is, when I could hear the dialog clearly, the explosions were loud enough that I was worried I would wake up my wife.
Overall I like the feature and will use it often.