I see your point Daniel, I was wrong to have assumed they were in the same room - obviously we don't know what settings they currently have so I would always set the BV5, if acting as a link room set to V.OPT 6 and the stereo to A.OPT 1 if these are the only two items in the house.
IMHO the speakers in the BV5 give a tremendous reproduction for a TV, however unless you were to put Beolab 4000 an equal distance apart I would struggle to make a comparison but I assume that the 4000's would be better, but then again they are not housed in the BV5 cabinet.