Also, need to consider if there are any issues with downloading from torrents or unauthorized sources since iTunes is a legitimate store, but "rip" might mean a user-generated copy. Also, 320kbps VBR should be high quality, but variable bit rate files can vary in quality per track. M4A is Apple's container, so compatibility might be a point. Some devices might prefer ALAC for lossless, but M4A is lossy (MP4/AAC).