In spite of my earlier post and jokes at the accordians expense, I do actually like the sound. I think what gets to me sometimes is the songs that they are used in - just not my cup of tea. But a fine instrument that I wouldn't mind learning to play (but man, they can get pricey).
Re: the guitar B string - I tune mine a bit flat on purpose. What you don't want is a flat G string (if you are a man).