The x series guitars are equiped with active emg's, in the most expensive models/ or with floyd rose.
The other models came with passive emg's or duncan designed's.
Are'nt duncan designed's "inferior" even to passive emg's? Should'nt all x series guitars came with the best features? Why rrxt have duncan designd?
What "Duncan Designed" means is that they used the standard Seymour Duncan schematic (I'm guessing for the Jazz neck and JB bridge models) and manufactured them overseas. If done right, it should be pretty darned close to a USA Duncan. For the record, the X-series guitars are also made overseas, likely in the same shops, so the Duncan-designed pickups make a lot of sense in that context.
EMG makes some great bass pickups, but their guitar pickups have never impressed me.
Long story short-- if you want the very best, get something from the custom shop.
Otherwise, it's not like there's a shortage of pickup options in the aftermarket...