i appreciate that the majority of Nexus owners probably don't use sync, i haven't really bothered with it much either but when i first got my players i tried it out and didn't think it felt particularly 'tight' and haven't really touched it since.
after installing the new firmware and saw some improvements to sync in the log, i had a bit of a play with it last night and found it still didn't work properly. two properly beatgridded tracks, that play perfectly in time when synced together for the full 7 minutes or so should not be going out of time (by a tiny fraction) when using quantised loops and quantised hotcues should it? this tiny fraction is enough to trainwreck a mix which would prevent me ever using it in its current form.
i've played using sync on traktor a couple of times and it is really tight and you can loop and hotcue all you want and it doesn't skip a beat, the nexus however feels and sounds sloppy in comparison.
master tempo was on last night, i might try a few more experiments in the next few days with it off - it could well be MT causing the glitches based on past experiences...