I'm a Mac user myself, and actually turned to AM because it was the only nice frontend for MAME on the Mac
![Cheesy :D](http://forum.attractmode.org/Smileys/default/cheesy.gif)
I had my issues in the past: AM 2.1 was good but many themes using surfaces or making use of other features crawled and had a lot of issues, then I upgraded to 2.2 and 2.3, both unofficial builds using homebrew to provide the missing libraries. These were much better, especially 2.3, I never had great issues with that. And from 2.4 we finally have an official build so I got rid of homebrew.
I'm not having any issues with that, at least I don't see much differences between my Windows 7 test machine and my Macbook Pro Retina 13" Late 2013. There is an issue with glsl shaders though, on the Mac some features are not supported, don't know if it's my graphics card (Iris), the drivers or the libraries that are used by AM. This is not a great issue though, all the themes I tested work, just some shaders I built using GL3 or GL4 commands gave me issues.
Oh, one thing I noticed is that I can only use "software" video decoding, that's why when using video-heavy themes the fan starts spinning at full speed and my mac makes the noise of a jet engine
![Cheesy :D](http://forum.attractmode.org/Smileys/default/cheesy.gif)