To the best that I can understand the lawyer-ese in the very complex PSPU user license agreement, they will let you install it on 2 machines (such as 1 home and 1 work, or 1 PC and 1 laptop). Both of these apps are 'sub $50 US but very powerful alternatives to Photoshop.' Cost is not a deciding factor between them.

However, given you can periodically get Photo on sale for $35, I see overall they are both in a very close price range no matter how you look at it. It's also worth noting you can get a standard version of PSP that has 100% of the same features as PSPU in the app, for typically around $39.99, and it simply omits all the bundled extras. Paintshop Pro 2019 Ultimate (PSPU) costs the same as Photo does currently ($49.99 US), although both go on sale at times and I got Photo for $35 on sale. Some things I've observed, though I haven't done an exhaustive side-by-side comparison: Not interested in any unfriendly or irrational bashing of either one. Pro or con, I'm interested in objective differences (as in 'X supports this feature, Y does not'), and subjective preferences ('I like X because.').

Super interested to hear the views of anyone who's tried BOTH. TLDR summary: As an owner and user of both Affinity Photo 1.6, and Corel's Paintshop Pro 2019, I have come to prefer Photo as my primary graphics editor.

Corel paintshop photo pro vs photoshop