Cool, I went back and read some of your scattered comments about the MS300 and for what I want them I think I'd be happier with the M-80. Might give the MS400 another look, but that thin double sided cable is a big turn off. Seems like the M-80 are better in almost every way other than not being collapsible.
I like the MS300 but I really don't think it can compete with the M-80 on sound. It's a bit more comfortable, though.