You really need to sit down with a Photoshop user to see how they feel about it and how they approach alternatives; it took me no time to adapt from Photoshop + Wacom tablet to Affinity Photo + Wacom tablet, but I know photographers who won't because it's "not right".
Serif had more luck converting Illustrator users to Affinity Designer, and made the right decision to release Designer first, because Illustrator users were much more frustrated with Adobe, and because giving those users what they wanted helped get past the way the app does not "feel" exactly the same.
There is no way that a "pixel-accurate compliance" test suite can capture what it is that makes these applications the way they are.
its a little impressive that models have a compressed approximation of photoshop inside that works with minimal tinkering.
the icon for windows doesnt work.