Qms is a function of suspension compliance. I wouldn't say there are "better" or "worse" values - more like they're a necessary consequence of the system. Total damping is much more set by the electrical Qes than the mechanical Qms of the suspension. The thing is, the driver's mass affects the Qms value, and mass is definitely an important criteria. Qms values will indirectly show this but don't let that confuse you. I would probably not focus on one Thiele/Small parameter because that is short sided. Instead, look at the whole picture. Hornresp simulations will help you to do this.