It's tough to answer this. I played the first for 30+ hours, the second for 10.
They're okay. It's fun to build a park from scratch and make it look nice, but the game lacks building/asset option variety to really make the park your own. There are only a handful of buildings and most buildings have like two different skins. In a park builder I expect 100 different signs, benches, street lights, trees and shrubbery, kiosks and all that stuff but none of that is in these games. The games lack customization options.
The crowds are not interactive and it's basically all smoke and mirrors making the whole thing feel kind of shallow. For instance, they don't actually enter attractions or buy things at stalls, but just phase in and out of buildings. Rollercoaster Tycoon did it better.
It also doesn't really have economy micromanagement or other things you'd expect from the same dev that did Planet Coaster and Planet Zoo, two games that completely overwhelm you with micromanagement.
It's not bad, it's just a super light experience. Buy it when it's on sale.