ALAC supports up to 24/192. The codex had been reverse engineered more than 7 years ago. XLD for OSX can convert to and from ALAC to anything else (FLAC, MP3).
There is one advantage to ALAC. It seems to draw less power than FLAC making for slightly better battery life. However, file size is slightly larger than FLAC.
Both are 100% lossless. If you hear a difference between FLAC, ALAC, WAV, and AIFF- your computer is broken.