99buggers It really depends on the goal and function of the part you're printing. PETCF will be better in humid environments only for the reason that it doesnt absorb much moisture. Nylons are fine in humid environments, you just need to be aware that their mechanical properties change with saturation.
Filled nylons will get softer and gain impact resistance. They may creep more too, but is it a measurable difference? Again it depends on what your're making. So sorry the answer seems to be a bit of a "it depends", but each material has its own advantages. PETCF is definitely MORE MECHANICALLY CONSISTENT in varying humidity but filled nylons by no means lose to it as long as its mechanical properties in your environment fit your desired need!
