I have deep dived the mono box set and the stereo version of Abbey Road. I am very impressed with the remastering, end to end. The earlier work has never sounded better, IMHO. The mono mixes throw a wonderful soundstage, and really sound great on less than pristine playback systems like car stereos.
Most of the work up to the White album was mixed on tube-based gear. This sounds incredible. The stereo version of Abbey Road was recorded and mixed on solid state gear, and due to them personally needing more than 8 tracks, suffer with a little bit of compression that was a by-product of the mixing down. You can particularly this on the fade out of "I want you". Overall, you get more enhanced presence of Ringo and Paul and their special interplay. The deep basslines on the White Album are especially brilliant and I think the skins on "Carry That Weight" are as close to drumming perfection.