Tat has gifted us with a build of the 21 August 2010 git snapshot. Get it at the usual place: http://macflightgear.sourceforge.net/home/
Check out the new urban texture shader (hint: there's a new performance-quality slider in the rendering dialog, and you'll need to move it to the right). The mountain and other land textures are improved, too.
This build runs well on my new low-end iMac, but video cards older than a year or so may not give usable frame rates. It takes more graphic horsepower than 2.0 to run all the goodies. It crashes on me fairly regularly, but oh, my, it's pretty.
Be aware that some 1.9.1 or 2.0 aircraft won't work well, or maybe at all. Some won't even load. There are bugs, which Tat can use your help in fixing. Send him your crash reports and log files, along with your configuration and what you were doing.