Is there anything that compares to their absolute dominance? Every one is using their CDJs these days. Occasionally people still break out the steel wheels but Pioneer seem to have completely captured the market.
Allen & Heath Xone 96 (or previous 92 model) mixers are very popular in the techno world.
Pioneer DJMs have dozens of FX combinations to aid with fast/fancy transitions, whereas techno/trance (and similar) genres that rely on long smooth blends like the extra EQ channel and filters.
I don't know any hip-hop DJs that use Xones?
The Xones are also analogue vs digital Pioneer mixers which also plays a part in audio quality, especially if the source is analogue (vinyl, rack modules, etc).
I'm happy with my Pioneer DJM-750mk2... but also happy to exchange a kidney for Xone:96 :-)
Inertia, plus in the grand scheme of things CDJs aren’t too expensive for clubs.
Two CDJs cost less than weekend’s worth of personnel for a small club even.
If you’re a DJ that’s just starting out, it suck’s a little though. Usually you’ll start out on Native Instruments’ Traktor S2/S4 or Pioneer’s cheaper DDJ, and for your first club set you arrive early so you can familiarize yourself with the quirks of the CDJs. Or find a buddy with a CDJ home setup that you can practice on.
A big reason is the Rekordbox software used to manage song libraries. Another is standardization - DJs move from club to club and encounter the same hardware setup. They are very well built, work in rain, ...
Today you also have influencers which are DJ-ing, but they don't have the skills, so either they have a pre-recorded mix or just use the CDJ auto-mixing features. Having a standard device they know how to operate is again critical.