DCA's tower has a far more impressive boiler room (and creepier with all of the Twilight Zone references, like the boiler resembing a face, the stairway to nothingness, the chalk door into the Twilight Zone, and the fact that the show rooms are at different points depending on which elevator you enter (either the mirror room is above or below the ghost scene, and it's not the same in all three shafts) adds variation. Furthermore, the drop sequence seems scarier as they have done what I have wanted wdw to do for years--had one of the drops feature the elevator doors not opening, which is even scarier at night. DCA's Tower also has some nice new dialogue, more impressive special effects (as we would expect after 10 years--even creepier ghosts, an impressive mirror effect, even more use of the star fields) and a more seamless elevator system. For example, the elevator doors during show scenes now open as you are arriving at that floor, which makes the ride flow better (no pauses) and being that the entire ride takes place in the drop shaft, the elevator can (and does) use the shaking effect in one of the show scenes, not just the drops. Further, I find the time right before the drop far creepier, with the added echoing effect in Serling's voice during the "One stormy night long ago..." spiel. Finally, I find the elevator doors opening at the end of the hallway to reveal the ghosts, then dropping before you drop is just creepier. It kind of has the effect of making guests lean forward to focus on the elevator and kinda think "what the..." and then WHAM, you drop (as opposed to MGM, where you sit in the dark for 3 seconds, waiting--also scary, but in a different way). I would go so far as to say the Orlando version is much better from the end of Sunset Blvd through the library (that is to say, the entire outside and the lobby) and the DCA version is better from the library onward--better boiler room and a creepier, darker, smoother ride.
Never the Same Fear Twice has four drop sequences--two go up first, two drop first, all feature the same number of drops as DCA's ToT--something between 3½ and 4, along with several smaller drops.