I don't mind ambient songs with piano is it's very subtle and soft. I don't like piano if it's sharp or the focus of the song. The music titled "What Matters Most" by Nathaniel Rembrandt is a perfect example of soft piano that I am ok with. I do, however, prefer no piano overall or too dominant among the suggestion, but a few with piano, if soft, is ok. The song "Underneath" is a terrible suggestion and is not ambient.