Played many new and old games this summer in Germany that had full playfield protectors. My opinion is they look fine and will keep your playfield mint but I found it changed the way each game played for sure.
It's a totally different surface that the ball is traveling on so seemed a bit faster for sure and spin imparted on the ball feels different somehow. I'm not saying it was totally different but if you are a home collector, beware it will play at least a bit differently than before. I would say purists may have 2nd thoughts but if you're main goal is to protect then this looks like a great solution.