This is cool, i'd use it. Its quick to get an idea of what font to use. A few improvements (using chrome):
1) Didnt know I can change the text that says 'Logo.' Took me a while to click the text and change it. Indicate that somewhere.
2) It would be cool if I was able to change the background as well.
3) In the drop downs, it would be awesome to see images of sample text of that font.
4) Letter spacing would also be awesome.
That's about it for now. Keep up the good work! Looks cool!