Tom -
Do Apple Lossless. First of all, as you do more listening, you will end up there anyhow. That is 100% a universally held opinion and a basic tenet to getting the most out of your system.
More to the point, since you are using this professionally, an Apple Lossless file can be converted to an AIFF, WAV or other format that you may want or have to use in the future. An AAC cannot since the data has been lost.
Do Apple Lossless. First of all, as you do more listening, you will end up there anyhow. That is 100% a universally held opinion and a basic tenet to getting the most out of your system.
More to the point, since you are using this professionally, an Apple Lossless file can be converted to an AIFF, WAV or other format that you may want or have to use in the future. An AAC cannot since the data has been lost.