My wife and I rode SM at WDW right before they added the audio. I would have to say that the DLR version was way better prior to that. The DL track is smoother, the ride vehicle is DEFINATELY more comfortable, and the soundtrack is great. The WDW spaceship prop on the first hill is cool, and the interactive queue is cool, but the ride itself left me unimpressed. I watched a youtube video of the audio they installed and it looks like they did it on the cheap. As with California Screamin, the SM audio is synched to the ride and the music mimicks the dips and curves in the track. I believe it is radio controlled as well to make sure that the audio is perfectly synchronized (I recall hearing it skip ahead a bit before).
DLR has the photo as a surprise at the end rather than at the beginning before you have even started the ride. What is the point of having a picture then? Why not take it while you are waiting in line?
Finally, one other minor detail is that the DLR queue is less claustrophobic because it starts outside on the side of the actual ride building. You do not have to walk through an endless hallway like the one in MK.