I worked in a studio for a 'world music' record company, as the engineer. I hated mixing. Either I'd be recording/mixing exotic instruments I'd never heard before, or I'd be taking the unmixed stuff recorded in another country with inferior equipment, try to clean it up, and then mix it. I absolutely hate that part of the music process. It bores the crap out of me, it's tedious. I'd much rather work with an engineer who knows this stuff, intuitively. There's certainly an art to it.
Actually, though, mixing ambient music is not nearly as easy as what it seems, as spatial issues matter a lot more. Robert Rich has a lot to say about this over on his website, I'd made a cheatsheat of his best points, if I can find it, I'll share.