I know lots, although I'm not one of them, I'd take a BD over an up scaled DVD any day. I remember the first time it really hit home to me was when I watched the first few episodes of 'Dollhouse' on DVD and half way through got the BD. I was kinda blown away at home much older the actors looked just because you could see their wrinkles clearer. Just one striking example that anyone would notice, but of course everything looks so much clearer.
Audio I'm not so fussy on though, I'd probably not tell the difference between a BD and DVD in that area.