I try to always get a scope designed for air rifles.
Firearms have a single recoil back. Air rifles get 2 recoils, one forward and one backwards. The extra recoil is due to the spring (coil or pneumatic piston). The result is that firearms scopes on an air rifle will result in cracks on the edges of the lenses and optics over time, but an air rifle scope on a firearm will just take the beating and continue.
And although there are lots of cheap air rifle optics designed for $100 guns, there are also some very good air rifle optics that rival the firearms scopes in quality (and price).
I purchased a PCP last year and while pricey, I love it. No recoil and very quiet.....
There's no limit on the number of optics available for it, it just comes down to what you want to spend.