Remember, I want one that you can actually play against, not one just for analysis.
FREE Chess GUI for Mac OS X 10.9 that you can play against?

Don't mean to toot my own horn, but I ported Xboard to an OSX app
http://www.open-aurec.com/wbforum/viewtopic.php?f=19&t=52964
I recently found Jerry: http://asdfjkl.github.io/jerry/
It's a quite simple program without so many features, but available for OS X, and you can adjust the engine strength.

I find it bizarrly coincdental that it was written by your country man, and you recommend it on an ancient mac gui thread not knowing that the OSX build infact exits with an "Illiegal Instruction 4" upon launch.
I bet you didn't find it at all, and that you're the author. :)
If I'm right, own up to it! It's quite and acievement. No need to be coy.
It's great to see more OSX chess software. There isn't enough good ones. I couldn't write my own, which is why I went through all that trouble making a useful package of an existing Unix one.
You're right that I am biased - the author is a good friend of mine and asked me to spread the word. But I did _not_ write it.

Nothing wrong with that at all, even the biased bit. :) I just had issue with the "I found" part when it didn't look like it. If you said, "Hey check out this software my friend wrote," I wouldn't have thought anything of it. Never the less, in retrospect, I'm sorry to call you out. It really doesn't matter that much. I just don't like lies, even modest, innocent ones.
But like I said, we need more OSX Chess UI's. Especially those that aren't java.
Sigma Chess obviousely does not work. The free version of Shredder, well, I can not configure the ELO of the engine. Most other chess programs are... well... a bit terrible. Do you know any good FREE (by free I mean free 0 dollars, euros, pounds, shekel, yen, whatever) chess programs that work on Mac OS X Mavericks?