Recs.
Updated
Specs
Pros
Pro Numerous and varied campaign settings
TSR published many fully-developed and well-received game worlds for AD&D 2nd Edition, spanning a variety of fantasy themes. Examples include Dark Sun, Hollow World, Planescape and Spelljammer.
Pro Optional rules
2nd Edition AD&D presents a number of optional rules DMs can implement in their campaigns if they wish. Later books in the line, the Players' Option books and the revised core rulebooks, offered alternate rules to customize games according to preference. Some of these rules were incorporated into 3rd Edition, yet in 2nd, none are necessary to play the game.
Pro Very challenging
2E causes players to re-think their decisions before engaging in risky behavior. Death can happen at any stage, and there won't be a chain of saving throws to stave off the reaper: You reach 0 HP, you're dead! Much of the focus, then, reverts to problem solving and role playing.
Pro Interesting and unique proficiency system and rouge skill system
Only AD&D has the proficiency system, which makes each character unique and leaves room for rouges to prioritize their own skills, completely separate.
In later editions the skill systems are jumbled together, making rouges redundant.
Pro Made by TSR in the golden age of DnD
Last version of DnD created by creative founder Gary Gygax and a company that wanted to give people infinity opportunities, as opposed to Wizard’s of the Coast, who aim purely for profit and the lowest common denominator among their target groups. Each AD&D product contains more goodies: Maps, player handouts, local monster tables etc.