PaintShop Pro is very capable, but it’s a big installation, and can be extremely flaky, slow and unreliable on a lot of machines, without there being any obvious rhyme or reason to it.
On1 Photo Raw is primarily a Raw converter with editing capability, rather than an image editor: and in my experience (I do a bit of photography and I’m pretty demanding about my end-results) it’s a work in progress; and overpriced for what it is.
I’ve been a satisfied PhotoShop user for years (I even liked the subscription pricing model, and I don’t see Adobe as the Devil Incarnate), but – like a lot of folk – I’ve moved to Affinity Photo, and can’t see that changing any time soon…
It’s important to point out that even though two packages might have similar functionality, they won’t have the same capability – as anyone who has tried to effectively recover highlights or deal with high ISO noise without killing detail – will know.