It's also per-instance, so if you use one to run a build or automated test suite and tear it down afterwards, it costs you 24 hours each time. Some simple napkin math: if you average running two builds/test runs per day, not including weekends, you'll pay somewhere over $12k/yr. Crazy.

We test some cross-platform software with an installer, and there's automated tests for every Windows version since 7, dozens of various Linux distros/versions (including x86 and ARM), but we never got around to automating Mac largely because of the complexity with getting back to a "clean" environment (eg: what you get with a fresh EC2 image). Having relatively few users compared to all other platforms plus the cost being a couple of orders of magnitude higher, I doubt we'll take advantage of this. Too bad.