It's a shame we don't get the theatrical screenings in the UK, but I was lucky enough to watch The Best of Both Worlds blu-ray on a friend's projector screen last night, and the quality is absolutely fantastic. It does not look 24 years at all, it looks positively brand new. The picture is crisp and clear and the newly composited special effects looks outstanding.
By comparison, we watched season 2's 'Q Who' beforehand, and although it's nice and clean and sharp, the extra sparkle that CBS-Digital adds in-house just isn't there. The ships don't blend with the backgrounds quite right, they're too washed out, and the big pull-out reveal of the Borg interior (which is supposed to be a an awe-inspiring moment), was spoiled somewhat by the overly smooth picture due to excessive grain removal. One thing they did improve on is when the dead Borg drone in engineering disappears, there's now an excellent dissolve effect and a burn mark on the carpet.
Aside from that, CBS-Digital's work is just so much better. Better colours, better constrast and yet it still looks how you remember it looking. Just when you get used to everything being in HD, those three seconds of upconverted footage appear, and when it happened we all went "bleugh! WTF?" (or words to that effect), as we were suddenly reminded of just how awful the show actually used to look.
It's lovely now, though. I must have them all in HD! I just need to sell one of my livers to afford it. It's okay, I can get by with just one.