I would say the main thing that makes DL's attractions better is that over there, they are not limited by torrential rain, so more attractions load outside, and their exterior architecture is not so reliant on protective awnings. This doesn't seem like a huge difference, but believe me, the openness and freedom they are allowed over there due to the great weather is very noticeable.
Purely from a ride experience perspective, I would say that the Haunted Mansion in WDW is now better than its DL counterpart, thanks to the recent upgrades which actually added more to the attraction than were added at DL. I haven't actually ridden WDW's new HM yet, but that's the consensus among those who have.
With Winnie-the-Pooh, it's a toss-up. DL has these cute, longer vehicles shaped like beehives. It also loads outside in a lush forest. But WDW has honeypots which bounce up and down, which is a nice touch.
Tower of Terror is definitely better at WDW, as its elevators do more than just go up and down.
Is it worth it to go to DL when most of the same attractions can be found over in FL? Absolutely! Going to DL is like coming home and finding your living room redecorated and the furniture moved around in a way you never thought you would like. It's wonderful to change things up once in a while. Plus, there are some DL exclusives like Indiana Jones and the Temple of the Forbidden Eye, which, in my opinion, is Disney's best attraction *anywhere*.