Of all the $600 speakers I've auditioned, the JMLab Chorus 707 impressed me the most. The Monitor Audio B2 is no slouch either. I've never auditioned the Dynaudio Audience 42s, but I've heard they are excellent.
Of the three you listed, I think I'd go with the B&W's.
Just curious -- with a benchmark of $600 why aren't you looking at the Paradigm Monitor 5 instead of the 3?
BTW, for about $80 more you could get a pair of Paradigm Studio 20s. Not too much more money for a big leap in SQ, IMHO.
Odyssey Epiphony by far the best at this price and the rest as follows: Epos ELS 3 $329,B&W $600,Totem Dreamcatcher $450,Bohlender Graebner Radzia Z-1 $499,Wharfedale Diamond 9.1 $349.I wanna include Tims Lings but I cant yet and Eddie has the Ascends covered.