While the scene and the major parts of the scenes are duplicated for each side, it's not exactly a mirror image. There are small differences but so minute it really doesn't matter which side you ride on.
The only part that is different is the outside the show building there is more detail on the right side of the subs because they had more space to add details but once you are inside it just about the same. I don't know from the orignal attraction but Nemo is simular but same.
Sitting on the left side you can see the spur track to take the subs to dry dock. Of course I like to look at the ride with my face near the glass and not just sitting back looking outside the porthole.