If you're thinking about manual painting, then i suggest to also consider Mari, from what i've heard, it's basically photoshop in 3D. Painter's main strength and focus is proceduralism, it's very good at procedurally generating various textures and effects, but has rather limited toolset for actual painting.
Regarding hardware, i think that if you want to create assets that meats today's quality standards, you need to have capable pc, regardless of sowtfare that you use. Even if Painter lets you work at low resolution, it still requires adequate machine to process all the data, i had lots of crashes in Painter 1.x due to insufficient RAM or VRAM. Although performance and stability was much improved in Painter 2.x and 2018.x, it still requires decent pc to work somehow comfortabily.