Many-a-time did Legends come so incredibly close to conveying a beautiful atmosphere where the music, artwork and gameplay all fall into blissful harmony, but it never at any point actually did for me. In Rayman 3, while it wasn't a natural thing like it was in the previous games, for the times it tried to create an atmosphere, it hit the nail on the head. That's why I will likely always find Rayman 3 to be more replayable and memorable than Legends.
Whenever I play a Rayman game, there are always certain parts in each game I can't wait to reach just because of how wonderful they are; take Bongo Hills' rolling greenery, take the first entrance to The Cave of Bad Dreams, take the buildup to the Reflux battle and chasing down Razoff, those are all examples out of many of moments in the trilogy that make me want to go and replay them right away. There was nothing like that in Origins or Legends (except for maybe The Reveal, maybe). There's no stylistic unity in them, there's no flowing beginning middle and end, it's just a big mash of action and random.