Worked in the office acoustics world for awhile including coding a simulation for acoustics within both cubicle environments and private office to private office environments:
The most important sound paths in most office spaces are refraction ( low cubicle walls may as well not be there, just because you can't see your neighbor over a 48" cubicle wall doesn't mean that wall in contributing much of anything to sound isolation ) and reflection ( hard walls, cheap ceiling tiles, ceiling air vents with open air returns, etc ).
"Movable Walls" vary widely in their absorption profile, as do ceiling tiles. In both cases high quality models are fine. Most issues with movable walls had nothing to do with their absorption profile but rather poor installation/fitting causing 1/4" air gaps around the edges creating a perfect refraction and / or reflection path for sound.
The most important sound paths in most office spaces are refraction ( low cubicle walls may as well not be there, just because you can't see your neighbor over a 48" cubicle wall doesn't mean that wall in contributing much of anything to sound isolation ) and reflection ( hard walls, cheap ceiling tiles, ceiling air vents with open air returns, etc ).
"Movable Walls" vary widely in their absorption profile, as do ceiling tiles. In both cases high quality models are fine. Most issues with movable walls had nothing to do with their absorption profile but rather poor installation/fitting causing 1/4" air gaps around the edges creating a perfect refraction and / or reflection path for sound.