Actually on a Mac with iTunes, if you want uncompressed music files, AIFF is your choice, not WAV. AIFF can retain all metadata, including album covers if you paste them in.
My 2500-album library is a mix of ALAC mainly, with about 10% as AIFF. And I've tested several albums over the past few years, having each as both ALAC and AIFF...and I don't believe there's any difference.
What helps keep the compressed ALAC and uncompressed AIFF sound the same as been powerful enough music servers which can decompress the ALAC files quickly.