Be sure to read up on some earlier posts on the subject of selecting a controller.
You will see we recommend the following steps:
1) Determine your (desired) workflow.
2) Find out what software most closely matches that workflow (you’ll never find a 100% match).
3) Determine a budget (so you don’t get distracted by way too expensive shiny lights and fancy buttons).
4) Select 2, max. 3 controllers that support your workflow, your software and your budget.
5) Try to get some hands-on with your top 2 or 3 controllers.
6) Make your decision.
As you can see, there is no room in this advice to pick a controller without first determining what you want in workflow and then choosing your software.
If you make the first step, it will automatically limit your software choices (i.e. lead you in the direction of one, perhaps two). Once you picked your software, the combined knowledge of your workflow and the software will narrow things down a lot.
I can safely say that Traktor and RekordBox DJ are two totally different softwares, aimed at totally different kinds of DJs. If you find out that Traktor software should be your choice, you are best off choosing Traktor/NI hardware. The S4 being 4-track/channel (do you really need it?) in a traditional design, the S5 more designed towards remix decks/stems use. This decision will be simple if you know what kind of workflow you want (what kind of DJ you are).
Unless you pick RekordBox and are 100% SURE! that you will never change to something else, the DDJ-RX could be good. If you are still finding your way and you think you might switch software in the near future, you’d be smarter to get a DDJ-SX2. It does work with RekordBox DJ, but can just as easily be used with Virtual DJ or Serato or Cross or …
Finally, you have to figure out (again following the steps mentioned above), if you already need a high end controller or if a more starter/medium controller would work well for you too. This also depends on HOW you have been DJ-ing for the last three years.
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