Hey,
I would (for now) go for the SX2. I’ve used the S4 and its no where near the controller of a SX2 (also used). If you liked Serato, and would like to eventually cross over to Rekordbox you can. However you can’t get the best of both with the RX as its specifically designed for Rekordbox. I do believe that Recordbox will eventually be better program, its taking a while to really be comparative to the power house of Serato. Good luck.
