The Zu Griewe gap is not difficult to adjust if you follow published directions and start at the reference 1/8" gap. Then you can go through a one-time exercise to get it right for your room and you're done. Devore and Zu are different experiences. Every Devore speaker I've heard has discontinuities between driver behaviors, but they become far easier to discern after hearing the coherence and unity behaviors of Zu. If you like the somewhat "rich," euphonic bass of Devore combined with a crossover constriction in the heart of midrange with a tweeter that is faster than the slow midrange driver, then shy away from the top-to-bottom consistency and coherence of crossoverless Zu. Steve Guttenberg flubbed his Soul 6 review. He did it too hastily, didn't work the Griewe Gap properly and got them (Zu's fault) with insufficient burn-in. He should have blasted them for 2-3 more weeks before doing the review. For more current perspectives on well-burned-in pairs, see John Darko's youtube review, and Srajan Ebean's 6Moons recent review. Both took more care in setup than Guttenberg did.
Soul Supreme is a room-friendly, amp-friendly speaker. The Radian 850 supertweeter is silky and the 16 ohms load makes most solid state amps sound cleaner and more musical than lower impedance speakers on same amps. If you use a tube amp without 16 ohm outputs or a SS amp of low power, you can use 25ohm parallel resistors at the speaker inputs to get a net load of ~8ohms.
Soul 6 is vivid, dispersive, room-filling, bass-impressing, despite its smaller size. The main driver and concentric supertweeter have a larger cone of dispersion, and the driver is energetically quick and percussive. The okoume cabinet with underlying superstructure is a champ at energy management and lightweight to boot. Soul 6 is easily the most coherent, unity-behaviors speaker in its price class, but this industry has trained customers to like a lot of low-unity speaker designs, so depending on your frame of reference, you might have to give a Soul 6 or even a Soul Supreme some time for you own mind to acclimate to holistic, phase-coherent sound, or you might love it right off the bat. Or you might not get there and reject it. That's why Zu gives you 2 months to find out. Soul 6 is easy to lift, pack up and return. You can do it all by yourself.
If you happen to be in Los Angeles, you can hear them on my systems.