i dislike having to rotate the bezel in any way except to take the bezel off and on.
like previously mentioned, some have loose threads and can cause wiggle, and depending on how much the bezel was loosened it can activate other modes by accidentally pressing the bezel.
more maintenace is also required. although it really isnt a factor, just clean the contacts every now and then.
i have an armytek predator, and although i like the options it gives me in terms of being able to program it. i dislike its UI even more than your typical fenix, because it require back and forth twisting of the bezel. its thread tolerances are pretty good so theres little wiggle, but 2-hand operation is a must.
for my uses, i like 1-hand operation, and i dont need more than 2 modes of brightness. so i like my lights to be very simple without any moving parts except the switch.