Where should I start reading?
It would depend what you want to read. If you want to read Batman, I would suggest starting at the New 52 Scott Snyder/Greg Capullo run. Then work your way up to Tom King, which personally I love, but can understand why people don’t like it as much. If you want to read Superman, just go right to Rebirth.
I would start with Rebirth because Rebirth is better and more recent. Just accept you will have a couple series where you’ll be like who is that? or what is that reference? But honestly Rebirth somewhat pretends New 52 never happened.
You can view my list for Rebirth here that’s DCU specific!
There is some pretty good stuff with the new 52. The early Batmans, Batman and Robin, Justice League, Green Lantern, early Batgirls.
Yeah, with New 52 just be aware that at least some of it doesn’t “count,” if you care about the ongoing DC story/big picture/continuity.
Always Gibby, I’m going to be redoing the guide at some point soon for the DC Unlimited Update. But hope you like it. I’m also doing a Rebirth Reading challenge to take you through the biggest moments of Rebirth. Starting with the Button. You can see that post here: https://www.dcuniverse.com/community/boards/comics/rebirth-reading-week-1-the
Also about New 52, you’re right there is some great stuff but its 5 years of similarly dark and depressing material. There are literally 52 LAUNCH series. And while about 7 of them are good. Most of them aren’t all that enjoyable.