I would agree with Terry. If you’re experienced with Traktor and mapping (which is a lot easier than most people make of it) I’d go with the Vestax. If not, Pioneer. I was going to go with DDJSX/Serato initially until I tried the demo version of Traktor. I liked it, and decided to stick with Traktor, so I ordered myself a Traktor bible which lays out in a very descriptive and easy to understand way, mapping any and all functions that Traktor can perform. It takes a little time to get it down, but once you get the ball rolling, not too bad.
Also, if you plan to do scratching and using the jogs a lot, I’d go with the DDJSX. From what I hear, mapping any jogs that aren’t Native Instruments’ to Traktor is less than optimal.
I am waiting for the next big Traktor controller. Either Pioneer’s DDJ-TX, or the VCI-400-II, or Kontrol S4/F1 combo. One of these has to be coming. Good luck!