I’m not a designer or artist, but I know what a good app does. It should make it easy for a non-expert to do something great. Acorn does that for me. It’s the application I turn to on my Mac when I need to fuss with images. It’s also incredibly powerful. It probably has everything you think you need in Photoshop but it’s easy to use and has terrific support (where you actually get a response from a real person with a real answer). Version 5 adds a bunch of stuff I probably won’t use but it also adds great stuff like EXIF editing and shape generators. I like applications made by people that actually use it. It’s also only $25. That’s like the price of one ironic snarky T-Shirt.