I'm listening to my first reissue: Sgt. Pepper's, stereo digipak.
I've never had a Beatles cd, and my Sgt. Pepper's is a mono lp bought when originally released. This stereo mix IS significantly different in some portions and the stereo sound of this music I know so well in mono is a bit disconcerting, in a very fun way.
They did a great job with this one, at least. Does not seem compressed, certainly not in the way we're used to, and very warm and clear.