I'm in the "small difference" group. Making your room more accoustically suitable will have more gain than getting lossless audio. I decided I wasn't going to put the time in to research room accoustics yet, so I went with a receiver that had room correction processing bult in, Audyssey. Audyssey made a much bigger improvement in my room than getting lossless audio. Same for my buddies setup, he's loves what Audyssey did.
Here's what happen when I set my buddies up:
(Going from a Denon 1508, no Audyssey and no lossless audio, to a 1908 with Audyssey MultEQ and PCM)
So I run Audyssey and play a BD for him. The Descent. I turn it to the scene where the tunnel collapses (we demo'd this scene pre receiver swap). His response was "holy ****, that sounds awesome!" Then I realize it's still on DD 5.1. lol I switch to PCM on the fly... nothing from him. Honestly, in his setup, if I did a blind a/b, I don't think I could tell, maybe on 1 or 2 movies, but certainly not everytime or most of the time. TO be fair, his speakers are the weak link, but his setup still sounds very good, his room is much better than mine from the start but my setup is alot better.
Bottom line, how much can you control your mind?
How much is that little extra worth? I needed it, I always want the best I can afford.