The S4 is great man, keep it.

The only way I'd ditch my S4 would be for 2 cdj-900/2000's and at least a djm 800 mixer. With the S4 we can do everything those units offer for a fraction of the price.

I've owned cdj 1000's and 800's and the only feature the cdjs have over the s4 is the ability to play a cd and a larger platter.