SkyFonts

Doesn't support fontspring accounts. But supports Fonts.com, MyFonts or Mosaic accounts and works with Google Fonts.

[Edited by s0me0ne, February 28]

I guess there's no need to beat about the bush. SkyFonts seems a a bit useless. I installed it, set up an account on MyFonts and linked it to the app, tried to "Sync Fonts", tried to get it to auto-install fonts from MyFonts like it says it should, but it would do nothing of the sort. The app's main window appears to do absolutely nothing. It's essentially just a graphic. The "Sync Fonts" button gives you no feedback. It's unclear whether it does or has done anything.

Everything else seems to work, e.g. settings menus. The app appears to be stable.

Given that the app doesn't seem to do, anything, but apparently needs to run constantly (on account of its complaints when you try to quit), I couldn't help but wonder if it was actually some sort of malware. A bitcoin miner, perhaps?

In any case, I've uninstalled it.. Give it a miss.