Just my opinion, as I thought progress was what we all look for.
If you're going to make a MacOS app or iOS app, start by using core system so you don't end up with either the glut of Adobe products, or the annoying use of such add-ons as X Windows. Affinity is another great one, although breaking up features into different apps seems a little greedy, as Illustration and Paint features should be cooked in to one delicious app (of course the price for development would reflect the feature set, it could never be as painful as Adobe's model). Inkscape so far as an Illustrator replacement has far outpaced GIMP improvements on the Photoshop front, which left me and many others to find other alternatives.
While Adobe dragged their proverbial asses on native system support for the Mac/iOS Pixelmator was one of the first to use native core OS integration on the Mac and iOS. Or even Inkscape for Illustrators if you're planning on ditching the Adobe blood-sucking machine. It’s also a serious app: Photoshop has a steep learning curve and will take practice, often over many years, to get to grips with. The fact that you can even mention it while leaving out a great app such as Pixelmator/Pixelmator Pro shows a lack of hands on research. Adobe Photoshop is the reference app when it comes to image editing and many years at the top haven’t dimmed its shine. GIMP is just outright crappy, unless you like the feel of UNIX X Window system built apps or old style Windows Apps. It's usually my go to when getting any of my artist buddy's in to the fold. ProCreate is a great app for sure, and especially for the price and feel for a traditionally trained artist.
