Given that kstrauser specified "an easy way to launch a single Amiga app in a window on my Mac," an Amiga emulator that only runs on Windows -- however good it may otherwise be -- is probably not in fact what they're looking for. :)
(Edit: I see that Cloanto does have a somewhat cryptic page for macOS, but the way I read it, Macs can only run the open source UAE that I gather Amiga Forever is built on top of. So https://fs-uae.net might be a better place to investigate.)
That’s exactly the one I use, with the ROMs and ADFs from Amiga Forever. Still wish I could double-click a Defender of the Crown icon and be playing it a moment later.
(Edit: I see that Cloanto does have a somewhat cryptic page for macOS, but the way I read it, Macs can only run the open source UAE that I gather Amiga Forever is built on top of. So https://fs-uae.net might be a better place to investigate.)