Adding a controller to my DVS-setup (Stick with traktor or go serato)

I'm siting on a Traktor A6 (with turntables and mixer) and a F1, but I need a controller as I'm temporarily living somewhere else because of University (The F1 I brought with me though). I've been looking at the DDJ SX and NS7 1/2 but was also waiting for NI to release another controller. I believe Serato has been stepping up, doing some really great stuff (the only thing at this moment I find Serato missing is a better sampler), but on the other hand I own these NI products. Do you guys believe the S4 mk2 would be a wise choice/something I could use later on with the turntables or should go with a Serato controller now when Live and DJ is merging?

(I posted this in the S4 mk2 thread but realised it should be it's own thread, doesnt look like the post was approved anyway so)