I've auditioned both speakers and ended up buying the monitor 5s. To me, they sounded alot more "alive" and detailed than the B&Ws. Once you get their positioning right, the soundstage is awesome, but keep in mind that they are rear ported and somehow, they produce a tremendous amount of bass. I had to pull mine about 24 inches away from the wall and plugged the ports to contain the bass. If you are planning on placing them in a built in bookshelf, IMO I don't think they will sound the way they should and you may end up being pretty dissapointed. Keep us posted as to what you end up going with.
Cheers
Shahen
Cheers
Shahen