Last night, my AD&D (2ND Ed.) group finally made it out of The Undermountain. We switched editions a few months ago and I've been very happy with the results. I've been a roleplaying geek since I was thirteen years old and I've played and gamemastered in numerous systems. I don't know why, maybe nostalgia, but to me, many of the earlier game systems seem better for actual roleplaying. AD&D/ D&D is a great example.
While First Edition had it's faults, mostly a slant towards powergaming and rules organization, Second Edition cleaned it up and stream lined the core rules (in my opinion). It's big problem was the tidal wave of optional rules that came later. Third Edition made some elements of the rules run more smoothly, but added books upon books of rules, not counting books from other companies published under the Open Gaming License. There was also a tendency to base everything on dice rolls. Roleplaying, though not quite gone, was being relegated more to random chance than previously (the two previous editions had charts for this, but the characters had to initiate roleplaying before rolling). In Fourth Edition, actual roleplaying is rarely mentioned in the books. The previous three editions had entire chapters dedicated to the subject; how to act in character, how to come up with a background, the difference between player and character knowledge, etc. Many people, including myself, think that the product has just become a money grab by a clueless company.
My party made it out of The Undermountain last night. It was a good feeling.