I've had a protector on my Mando for over a year. A lot of work to disassemble and re-populate the playfield. The protector from playfield protectors in Germany, is ill-fitting in a couple of areas and was corrected later after I had already re-populated the playfield. They did not respond to my pointing out the issue and asking if they could correct it and send me a properly fitting one, before I re-populated because I was not going to do it twice. Zero response from them and they changed the protector to my suggestions without notifying anyone, including me. So as to the protector itself, if designed to fit properly, it is worth the investment in time and money. I lightly wax the protector and do not have any issues with ball speed. The protector does get spot "wet" from suction to the playfield, not really wet just looks that way. I get ball hang ups where the protector does not fit correctly in the right orbit, but I am sure the new design probably solves that as I pointed it out to playfield protectors.

In summary, a playfield protector, IMHO, is worth the investment in time and money if it fits properly.