Other than the deeper red on the 13, the purple and light green on the 12, the blue on the XR, and the pink on the 7, I think Apple's 'colorways' across all their products are crap. They have either a muddy feel, like how someone with depression might see the world, or a washed-out amateur look. Don't get me started on those Watch exercise rings.
Maybe they are super sophisticated and I'm not cool enough to see it. Apple should look to Eddie Bauer instead for some color inspiration. I guess you could always get black or white, then buy whatever case you want.