I'm a pretty regular participant on the Hoffman forum and The Beatles are an endless topic of discussion. I think there is some consensus:
the early tube cut copies are preferable to the later masterings- rather than try to sort through this thicket at some cost, I found a first series UK Blue Box that gave me a easy point of entry- many of these sets were bought as gifts or simply forgotten. There is nothing "special" about the pressings- they were simply pulled together from the commercial releases at the time. There is a website dedicated to the various boxes issued in different countries. My box was largely unplayed.
The relatively recent mono reissues are quite good, and a great way to listen to those vaunted mixes- I'm not set up with a dedicated mono playback system, but these records still sound great.
I bought a few of the earlier (82) Japanese mono pressings- I think the recent Mono set makes these unnecessary (except for completists).
The German Horzu -2 pressing of Die Beatles is a well-known anomaly that is worth owning- it is a basically a flat transfer of the two tracks without any added reverb or mixing. Everything is hard panned left or right, but hearing The Beatles "unvarnished" is pretty cool. Some folks find the spread annoying- at a minimum, it's a novelty, and a cool record to own.
I have a few other odds and ends I picked up over the years, one of the white vinyl White Albums (mine is a UK that I believe was made for export; the German white vinyl one is, I believe, a DMM).
You can go as deep as you want on any band or album. The Beatles are an obvious motherlode for those obsessed with the details. Though I like to sort through pressings to find the best sonic representation, I consider myself a piker when it comes to The Beatles pressings and as @cd318 said, that way may lie madness.
Generally, though, the Hoffman site is worthwhile, particularly some of the older threads and posts by certain members who have owned and compared a variety of pressings of modern pop, hard rock and psych. There is also a trading forum open to members who have reached a post threshold, and I've purchased a few desirable copies at reasonable prices there.