I don’t have a favorite edition. Truthfully, I’m not even sure I can answer that question honestly. Some people have clear favorites, but I’m not sure I can effectively scrub nostalgia from my answer.
Way back when I started about 20 years ago, I played AD&D 2e. It was the game of games. Now, I recognize that they system has some warts, but I still feel like it’s entirely playable. I still love THAC0. Not because I think its easy to process, because it’s a little awkward. It’s because the entire armor class (read, “Defense”), and attack system is tightly packaged on one die.
In fact, every iteration of D&D has its own merits. The original version of D&D fits in one book. The Basic version most people tout for its quality has been beloved by gamers everywhere for over three decades. Then there’s the current version, 5e. It’s very much an attempt to revamp older editions. Not just the make this clear, but the product releases are all updates of classic campaigns.
In general, I’ve enjoyed D&D, and what it has offered to me. Each version of the game has come with its strength and weaknesses and its hard to say, “this one game is the best!” I just don’t feel that way. The exceptions are that I think Pathfinder is better than 3.X, and that 13th Age is superior to 4e. Barring that, the game is the game is the game. Edition wars suck, and I think whatever you like is what you should play.