Image editing is lacking compared to photoshop.

The user interface is a little clunky, but the brushes are nice and more than sufficient for the basic needs. Artrage is a cheap and simple alternative, if you are only interested in digital painting. The amount of customization options is overhelming at first, but the digital manual is excellent and explains everything in detail. It needs some time to get used to it, but it might be worth yout time. I would still recomment this as the best alternative for pure painting. Also it is a one time purchase, no subscriptions:) On the downside, the performance is still lacking compared to photoshop and image editing capabilities are nowhere near extensive. The newest version of Painter has made huge improvements to the usability and interface issues that plagued the program before. Corel Painter has the far better tools and a more natural feel when it comes to the pure painting and drawing experience. Photoshop's brush engine hasn't really changed much since its inception in Version 7.

If you are interested in digital illustration, there are many apps that are better suited to this than photoshop. If you want alternatives to certain workflows, you still can find many good programs out there:

Adobe has switched to the atrocious subscription model, fully aware of the fact, that there is no alternative for many users. There are many programs out there, that do certain things better than photoshop, but lack other features, that photoshop provides. Up until this day, there really is no substitute for Photoshop as a whole.

Best photoshop alternative