Hi all I don't like where the Mac platform is going with each new release of OS X, and that is why I'm starting to prepare the alternative. I'd like to leave any proprietary softwares and be able to switch platforms, if needed. I've purchased most of my albums through the iTunes store, which lets me download music in the m4a format. To be honest, I don't know if this is the best audio format at the moment. I have many questions: - do you know if I should keep using the m4a format? Is it portable and is this format available in other OS? I don't want however to have non-compressed files - my storage is a bit limited, especially if everything is a laptop. - if I wanted to stop buying m4a files (and therefore stop using iTunes store), which other stores would you recommend? - do you know if ID3 tags are stored in m4a files? I have hard time finding an answer to that question. Thanks so much in advance!