I think it is. I've been learning it partially through a friend, partially through trial and error, and partially through the tutorials here. Once you start to get the hang of things, it gets easier. You may find that before long you're not even thinking about them when you use them. For me, this is because while learning a particular feature takes effort, it commits to second nature easily enough because I end up using it so much. There's a lot of repetition in Photoshop to drill things in, and a lot of tools communicate their settings in similar enough ways.
I've never used Pixelmator, but honestly I'm not stepping away from PS/Gimp at this point simply because of the wealth of information on the both of them here.