ISO compliance would likely come into play when burning a disk, and then devices used to play back said disk would likely come into play.

With transfer speeds now I find MonkeysAudio to be great for 'temporarily' reducing file size while working on projects. It is easy to get a bit-for-bit copy at the other end. Then (when done) burning to standard CD is a non-issue. But that's just me. I like knowing that what will be heard on the other end is pretty well covered, rather than hoping for the best.
That said, I have had good results with VBR for the most part. But once it is compressed with any lossey codec it is forever lost, and mp3 is a lossey codec.

I do not work here, but the benefits are still awesome
Make your sound your own!