The core set has always largely been 2.5 books at most. (With the possible exception of 1e).Well, I would have liked an option between cover-to-cover and I read sections as needed, but I voted for the second option since it was closer.
I read most of it, skipping pretty much all of part 1 on world-building and half of part 2 since I am already good without reading that material. I started at chapter 5 and read all the rest.
I was actually really annoyed that the first 30% was IMO wasted space. I'm sure some people got value out of page 1-99, but not me.
I mostly spent time using the tables to create random dungeons and feeling a bit cheated in that there is no random encounter table for city streets.
From memory (which may be wrong) the 3.0 one was pretty good while the 3.5 one was mostly a waste of paper.I read it as a player'cause I want to ruin d&d mwa ha haha'cause at one point I was interested in running. idk why but the 3.5 dmg felt like getting a little salami as a treat while 5e just gives me the whole salami.