One of my personal training clients is a gamer. Well, generally lapsed gamer in any case. He used to play D&D - 3.5 as far as I can tell - when he was younger.
He and his friends have gotten a bit nostalgic for their D&D playing days. He dug out his old D&D books and they've been thinking about playing.
So the other day, between deadlifting and bench pressing, he asked me - "Do you recommend GURPS?"
My answer wasn't very eloquent, but it came down to this:
If you miss playing D&D, and you've got the D&D books, take them out and play D&D.
Because really, his question was, will playing GURPS satisfy my urge to play D&D the way we used to?
It might, but the easier way to do it is to just play the game you used to.
If his question was, "I'd like to play fantasy RPGs again, and we liked D&D but we want something different, do you recommend GURPS?" Or "I want to try GURPS, do you think that's a good idea?" or "I liked fantasy gaming but I didn't really like the D&D rules, do you recommend GURPS?" my answer would have been different. If it was just "Can you recommend a good fantasy game to me?" it would have been GURPS.
If he was going to play with us, the answer would be GURPS as well. It would be "We play GURPS, here's what you need to know before you walk in the door."
If he had none of his old D&D stuff, I would have pointed him either to GURPS for a whole new system, or Labyrinth Lord or told him to get a PDF of B/X D&D for something d20 based.
But it seemed to me that telling him to play GURPS was telling him to go the wrong way about scratching that "play the game we used to the way we used to" itch.
I did tell him where and how to find GURPS Lite, and told him to come to me with any questions. I hope he downloads it, reads it, likes it, and wants to play it. I still think GURPS does fantasy gaming very, very well and it's a complete blast. I think it does D&D-style dungeon crawling at least as well as D&D does in some respects. But it wasn't the answer to his real question.