I'm not familiar with the current state of FLAC but as of a few years ago ALAC offered better meta-data in the MP4 container. Part of the reason I abandoned FLAC years ago was constant problems with meta-data. I would often end up corrupt files post-tagging or the player would simply not show meta-data I had meticulously added to my bootleg collection. I got the sense at the time that there was a lack of agreement on how meta-data was supposed to work in FLAC files.
Note to uriel: your last few posts are all [dead] for some reason.
uriel 2 hours ago | link [dead]
Afaik FLAC this days uses an ogg container, which is where
the metadata goes, so support should be as good as for Ogg
Vorbis.
In practical terms, I have a huge collection of FLAC, and
never had trouble with metadata, sounds like a bug in
whatever player you were using.
The Ogg container is optional, and I can't say I've seen it used much, if ever - I gather its main use was for streaming. FLAC has its own metadata as part of the spec: http://flac.sourceforge.net/format.html#metadata_block
