I don't really have enough experience with lossless soundtracks on Blu Ray to give any definitive takes on the sound quality, but I did see I, Robot the other day, and experienced the lossless sound, and I have to admit that I was slightly dissapointed. Having just seen the movie prior to the PS3 DTS update, I had to rent it again, cause of all the praise for the sound.
It definitely sounded good, but it didn't blow me out of the water or anything. I would expect reference level to blow me out of the water. In fact, I think Alvin and the Chipmunks was more impressive. I, Robot is much better demo material, but I actually was more impressed with the improvement that I heard in Alvin and the Chipmunks.
Again, I haven't had enough experience with these lossless soundtracks, only having my new receiver for about 3 weeks, but as far as I could tell, I, Robot while maybe one of the best Tier 0's, should be in Tier 0 and not the reference tier. Maybe we are going to actually need a tier inbetween Reference and Tier 0, and maybe I, Robot belongs there.
Also, as shocking as it may seem, I think Alvin and the Chipmunks is Tier 0, lol. Of course, understand that Alvin is heavy on the surround channels, but it does have a really strong clarity and crispness factor, that I was suprised by. Also, it must be understood that I've heard the regular DTS track many times, before finally hearing the DTS HD MA track. So, it may have been more of a case of me hearing such a big improvement, and that impressing me, rather than it clearly standing above other lossless tracks on Blu Ray.