Fatheads are VERY dark sounding to me (even for a ribbon). I haven't heard them with strings, but I imagine they would lend a slightly colored, thick tone, which could sound cool. If you get one I would definitely consider upgrading to the Lundahl transformer, which would give it a wider frequency response and slightly more open sound...
All the cheap ribbon mic dealers are essentially rebranding Chinese mics, with a little bit of quality control. The big difference between them, in my opinion, is what modifications they offer. After a lot of research, I also ended up buying a mic from Open Plan (though unfortunately I don't live in Australia, so the shipping was expensive...) and I'm very happy with it.
