It's hard to know how you'll feel about it, everyone has a different perspective / tolerance level.
First off - having a playfield protector on means, obviously, your playfield is essentially untouched by the pinballs. This means no ball trails, smashed ball drop rollover switch holes, etc. But, the ball will wear and scratch the protector instead so it's not like its a panacea for wear & tear.
Playfield protectors can alter how a game plays. They will be slower than a waxed playfield, they will raise the floor of the playfield up slightly which might mean you have to adjust rollover switches, etc to compensate. They can create reflections that might be undesirable. They may trap dirt and debris underneath which would become difficult if not impossible to clean without removing it again, etc.
The TAF I bought had a brand new Mirko playfield with a full playfield protector fitted from new. The restorer made a big deal out of the fact that "no ball has ever touched the playfield". Initially I thought this was great, but it plays noticeably slower than my TZ and Tron which are double waxed. There are also a few areas where I can see dirt which I can't access, in one place in particular there is a wood splinter which actually forms a bump when you run your finger over it. There are also a couple of areas where grease, moisture or some other liquid sits between the protector and the playfield, which will never go away. It has on a couple of occasions lifted up slightly which has meant I've had to remove the glass to reposition it back down again.
I'm planning to remove mine when I get the chance, simply because my playfield is already clearcoated and the usage it gets does not warrant having the additional protection given by the protector. I tend to look at it as one of those "bonnet bra" (hood I guess in the States) which protects your car from stonechips at the cost of making it look terrible. You're compromising your own enjoyment of it for the benefit of the next owner.