In all of this computer audio, Mac or other, keep in mind that the analog to digital conversion is vital and key to the resulting sound, far more important than what DAW software you use to work with it once in the computer. General pro audio wisdom says to have the A/D convertor outside of the computer, not internal, and almost never use the computer's internal soundcard for the conversion. Though there may be no problem with what is inside your particular box.
I do my conversions outside the box with a seriously upgraded Digi 002 box, or a separate
Sound Devices recorder. Using the external recorder with its
excellent A/D leaves the Mac free to work with files at the same
time. I personally almost never record directly into any computer any
more, just copy from flash cards. Way more efficient and multitasking
that way for me.