I have next to no experience working with digital image editing, and I'm planning on diving headlong into making a map. I have both Pixelmator and Photoshop CS5, and am wondering which one I should use.

I find Pixelmator's interface more user-friendly, but I want to be on the same page as the rest you guys and be able to use all the great tutorials and tips on this site, which tend to be for Photoshop/Gimp. I also don't want to get part way into the project using Pixelmator and realize I need Photoshop to do certain things.

Is it worth it for me to learn Photoshop?