For some simple photo manipulation Gimp works - but it seems a lot harder to use. Plus it's missing non-destructive adjustment layers, and the brush engine is nowhere near as advanced as photoshop.

Inkscape is similar - everything is a little harder to do - and there's some basic things that don't seem to be in the application at all. Does Inkscape support multiple artboards yet? What about exporting multiple resolutions without duplicating the assets? The symbol support also was very lackluster when I used it last.

Krita lags horribly every time I've tried to use it.

I like the notion that there are open source replacements for these systems.. and I'd love to drop my $50+ per month subscription - but the alternatives aren't yet equivalents.