I love YsL lines and shapes but Muse is one that i don't like at all..I think it is not comfortable and the shape is strange..
I advise you try both bags and then decide..Many times i had bought bags without seeing on me and then i never worn them because i don't feel relax..Good Luck!!
I just bought a medium Muse after looking at a BV as well. I love how functional and easy to carry the muse is. I mostly carry bals which are very unstructured but wanted a bag with some structure as a change. I think it looks so good either dressed up or down. I just wasn't feeling the love for the BV, but I haven't seen one broken in yet either. my vote goes to the muse.