Reply to Xone:DB4 or...DJM-2000 nexus

In the process of upgrading mixer-wise and have been seriously torn over the past few weeks between these mixers. I spent the past 6 years on Rane TTM hardware, then transitioned over to Traktor with a DJM-850...liked it a lot, but realized it wasn't enough for me.

I was set on the DJM-2000 nexus until I started looking more into the DB4 and the appeal of that range.
The selling point on the 2000 for me initially was the beatslicer and beat effect length buttons across the top (great for going bananas with slip rolls and such). Those are the main things I feel I would really be missing if I went with the DB4. Can slip roll type effects be done on the DB4 in similar fashion? I suppose something similar to the DJM beatslicer could be finagled with the combination of Ableton and TouchOSC/Lemur if someone got creative enough with it.

The only other thing about the 2000 I like a lot is the three EQ bands for the effect knobs...which would be great for isolating reverbs, echos, and aggressive type effects to the mid and higher frequencies without completely muddying up the lows...not sure if I can do that with the DB4 either. Hope someone can clarify.

What turns me off to the DJM line of mixers is how locked much of their functionality is to Rekordbox. Using Traktor, I feel like I'd be paying a lot of money for a lot of Pro DJ link integration which is only usable if you're running tracks through Rekordbox. AFAIK, I don't believe you can run your music through Traktor while simultaneously feeding DJM mixers beatgrid information from Rekordbox...not to mention this would require analyzing and managing all my tracks twice Is there a solution for this?
Whereas the DJM mixers quantize their beat effects from Rekordbox beatgrid information, my understanding is that I can lock the DB4 to the Traktor master clock, thus it will quantize it's effects to the Traktor beatgrids by default...much more preferable in my opinion. I understand you can do the opposite with the DJM and lock Traktor to the DJM clock...though I've heard some people have had trouble with this? Also, it seems like it would be much more preferable to have Traktor as the central timing hub, rather than Traktor constantly fluctuating while it tries to sync up your tracks to whatever the DJM is 'auto-detecting'?

Overall, pioneer mixers seem to offer a lot more quick to the punch instant gratification effects and functionality; and that is, I suspect, the reason why they've been the industry standard for so long along with the CDJ integration. The DB4 seems to have a much deeper side to it with more flexibility and nuances you pick up along the way...though I wonder if all the technical aspects overwhelm or spoil the experience of using it a bit.
From what I've read regarding build quality, sound quality, effects quality, and integration, all seem to make me lean a bit more to the DB4.