Which kind of motion platform would you recommend?

There are two motion platforms, a 6 dof system and a 3 dof system. I am thinking of adding a Vr motion rig in my VR arcade for both racing and flight sim. Obviously the 3 dof is cheaper but can be upgraded with another under chassis to make it into a 5/6 dof system. I just want to get some opionions from random internet strangers :) If you had any experience with any of these systems, which one would you prefer?