Yes. RTAudio is a cross-platform library for low-latency sound. That has clear advantages when you are releasing across several OS's like we are. I'm not sure how they compare when you are shooting for a OSX-exclusive application: PortAudio might be easier at the expense of hardships if you would later try to go cross-platform?

Oops, I mixed up PortAudio with CoreAudio here. PortAudio is -of course- portable. It's also open, like RTAudio and I don't know which one should be preferred for any given application.

Sorry if that caused confusion.

Kas.