Just got myself a Macbook Air, after using Linux based laptops for the last 10 years. Not necessarily a better experience, but need to test software on OSX as well - and it's never been straight forward to virtualize OSX.
Anyway, I saw immediately that the attempts to use native Mac look'n'feel didn't work very well with Frinika, so I set it to the same as used on Windows and Linux. So Frinika doesn't look like a Mac app anymore, but works better with Mac now.
One should be aware of some differences between Java 6 (made by Apple) and Java 7 (Oracle) on Mac OSX. I've noticed that the JTable behaves badly with Java 7 - and this is only on Mac OSX. This affects the Tracker panel when you try navigating with the arrows keys. You'll see that it tries to edit the cell, while on all other Platforms with Java 7 or Apple's Java 6 the navigation works as expected. At the moment I don't see any other solution than Oracle fixing this bug in Java 7 for OSX.
With the latest versions of Java 7 the JTable (table in the tracker panel) works much better. Only a few issues left (e.g. not able to select multiple cells and delete them) - but I'd say it's ok to use Java 7 also for OSX now. Eventually Java 7 will be a requirement for later versions of Frinika.