you can get your effects in time by tapping or scrolling to the right BPM on the 750. IMO the 900nxs doesn't have THAT much gain over it. Other than filters on each channel, but pioneer filters sound...
-dat 4 band eq
-dat ability to have mad control over effects if you want to add them externally
-filters HNNGG
-Pre eq cueing (get both tracks playing through...