what purpose? if you have GOBS of power and the rigth application - the solox can sound great [read: proper SQ install] and they can also be used strictly for SPL purposes
the w7 can get loud, and is more of a street beater "SQL" sub IMO - can get decently loud and sound fairly good. for SQ the jlw6v2 is the winner on JL's lineup.
but seriously, what kind of space and power are you talking about? and what are you trying to accomplish?