Yes, I'm currently using the XDJ's with Traktor at the moment (Connected via DJM-900NXS). Everything behaves as expected and the mapping of the XDJ to Traktor is flawless. The only thing not active at the moment is beat/loop jump, where your set loop length can be freely moved throughout other parts of the song. To be honest, I never use this so it's of no use to me. Also, the rev button has no function on the XDJ when running HID. Personally, I hope to see button mapped to something useful rather than being null (perhaps a 4th hot cue?). The jogs feel great as well. The reason I went with the XDJ setup is that in the even Traktor were to crash in a live setting, I can quickly change the XDJ mode and engage rekordbox through a media device I would have connected already to the XDJ (external HDD or flash stick, for example). It took me about 20 minutes to get use to the XDJ/Traktor setup, but it's implemented extremely well. Glad to see NI wised up and collab'd with Pioneer to get the HID developed. The only thing lacking is the animated wave form on the XDJ when connected to Traktor. You still have a static waveform that you can touch to scan through, but the only realtime wave form you can view is the one within Traktor. I'm willing to bet this will changed down the road (6 months to a year) once sales for NI products that have realtime waveform display (example: S8) have leveled off. Cheers.
P.S. If using a high-quality mixer/sound card setup a la DJM-900NXS, make sure to disable auto-gain, headroom and the limiter in Traktor's settings. These will drastically color your sound, not for the better. It almost sucks the "thump" out of the audio output.