I use Neutrino and its great!!! you need to get used to it because it has a LOT of functionality, loops, wraps, effects, but you can access to all AU and 3rd party plugins with it, it can use the iTunes library too, you can feed it with FLACs and a lot other formats... Try it and I'm sure you'll like it, I payed the license even before the trial ended.
PLAY is also great, very simple to use but for some strange reason it stopped working on my MacBookPro, so I switched to Neutrino.