Keep or Throw?

Hi all, I have recently acquired a dratini with 15HP/15ATK/5DEF 77.8% IVs with 679Cp (Level 29-30 approx). Do i keep it or throw it out(Prestiging is out of the question now). I have multiple good IV(abv 80 percent) dratinis and dragonites, so should I evolve and max out all other high IV dragons but still keep and evolve this one for later? Thanks