I purchased a WSD protector immediately after pre-ordering my phone, with plans to take the factory installed off and put on the WSD. But then the phone arrived, and I decided to leave the factory installed on until it got ratty or peeled and needed to be replaced. Thankfully - because I did have to exchange my first Note 10+ for another (SPen was waking up the phone every 5 seconds while IN the phone - making my phone a strobe light).
I've still not installed my WSD yet and I only have one case (so far - the Spigen Neo Hybrid), so I'm not pulling it off and on, which might start peeling the sides.
I love the look and feel of the WSD and my Note 8 was pristine when I removed it prior to sending it in for trade in. So, for now, the factory installed is fine - when it gets too many micro scratches for my liking, I'll rip it off and install the WSD.