The Collaborative International Dictionary of English v.0.48:

Advantageousness \Ad`van*ta"geous*ness\, n.
   Profitableness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

advantageousness
    n 1: the quality of being encouraging or promising of a
         successful outcome [syn: favorableness, favourableness,
         advantageousness, positivity, positiveness,
         profitableness] [ant: unfavorableness,
         unfavourableness]