I've included OSRIC, because I like playing it as well.
My answer is, that AD&D brings me back to a time of gaming, where it was fun. Where I remember my biggest worry in the world was, "Can I stay up late tonight?".
OK, well that is great, so it brings back memories for me, but that isn't it. The game is simple, and gives players and dungeon masters the room to think, branch out, and imagine. Its a game where, just because its not written in the book, doesn't mean you can't do it.
On the latest recording of RFI Podcast (it is still being edited), we talked about Non Weapon Prof's and Skills. A listener wrote in saying how he liked it and it helped guide players to what their character's background is, and what they can do.
This caused me to go on a small rant, because why does a player need it outline for him, what he can …