Recs.
Updated
Specs
Pros
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 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 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.
Cons
Con Lots of rules that a skilled DM can use to create the optimal experience
Con Core setting does not contain nudity, unlike 1e.
Due to concerns over public perception, for 2nd Edition TSR chose to eliminate mature themes and explicitly "evil" player options; remove references to angels, demons and devils; and otherwise smooth over potentially offensive content in the core game. This deliberate sanitization is easily reversed in personal play.