Is AD&D 2e worth learning and playing still? Especially compared to D&D 5e and other modern fantasy TTRPGs.
Everything I say keep in mind 2e is the version I have the least experience with. I have played it, but not for very long and not in depth. With that said I echo the response of others here. I would just choose either B/X, a B/X clone. Old School Essentials is a popular one. I was just talking about Swords & Wizardry Complete Revised a few posts up and that would be my person choice. You could also just run Rules Cyclopedia which you can get for free off of the Internet Archive.
I do not hold modern "DnD" very highly. So yes I would say it is worth trying the oldie butt goldies.
ACKS is pretty seated in Roman style fantasy world. If you like Roman stuff then you will love ACKS. If you don't then I am not sure I would choose it.
Here are a few recommendations to get you started;
- Rule Cyclopedia: This is the complete collation of BECMI rules. It is also free online. Even playing S&W I will still sometimes reference my RC to check a rule or a price of something if I can't find it in S&W.
- Old School Essentials: This is a very well formatted and cleaned up B/X. Much of what it says it says more concisely than the RC. It also has a good amount of content available for it and it even has a demon-themed kickstarter coming out next month, I think. OSE is definitely the biggest retroclone on the scene and it puts out a ton of modules and stuff.
- Swords & Wizardry Complete Revised: This is my current preference. It uses a lot of Holmes D&D style rules while being kind of hybridized into AD&D 1e. It is overall extremely simple to pick up and play and I found the formatting and language to my person taste. Also it is pretty cheap.
- ACKS II: B/X with some nice economic changes. I was nice enough to be given a copy to read through but I am not a fan of the world it sets itself in. I think it has useful rules but I would be hard pressed to run it specifically.
- Blueholme Journeymanne. If Holmes D&D had been the primary ruleset and was taken to higher levels. The Prentice version (aka rule lite stripped down version) is available for free on DriveThroughRPG. I like Holmes D&D so I like this, but again, I have S&W and prefer it. I do think that if given a week I could swap some of these rules out for either optional rules in S&W, OSE or even the RC and end up with a single favorite personal version of the game. But I won't do that because I am lazy.
- The Wightbox: Very early Chainmail B/X retroclone. Even Blueholme doesn't strip down this heavily. Pretty autistic attention to detail in faithfulness. There are a couple cool rulings here but unless you like reading that kind of thing probably not worth it for most people. I prefer to have more player options available than this, but I do like reading rules and interpretations.
If you would like recommendations on useful supplementary materials like modules or monster manuals I would be happy to point you to what I found purchased or "obtained" over the years and which ones I actually found useful.
Haven't actually played a fantasy game of GURPS, but it does seem like it'd be fun, I enjoy my historical/modern games because I had D&D overload from my friends exclusively running that.
I have played GURPS Dungeon Fantasy. It's pretty good. The campaign died out due to players not being able to make it, but if you can get a group and you love spreadsheets its really fun.