How helpful is the phonemic alphabet?

vor einem Jahr
I will never forget the looks of slow horror on my last student's faces when we started using a book that included phonemic transcriptions. They all looked up at me, stunned, with expressions that seemed to say "How could you? We trusted you." For teachers, have you had more success introducing the phonemic alphabet than I did? And for students, have you found it to be a useful tool?

I've also wondered how truly international the symbols are, as words can be transcribed differently by people with different accents. What do you think?