It varies a great deal, but usually there’s a tradeoff for planars, and that is that they have poor frequency response performance which is traded for less room interaction and an amazing ability to project an image.
That reduction in room interaction is really _the_ reason for planars.
One can argue however that this reduction in room interaction makes the planars more accurate from a practical stand point. What good is a flat speaker that you can’t hear as flat they argue.
In terms of distortion and frequency response, I haven’t seen a planar speaker since the Apogees that would measure as well as a dynamic speaker without enhancements from DSP.
Having said all of this, planars are worth consideration because what matters is how much you enjoy listening to music, not which is more accurate.

