User blog comment:Worldentertainment5/Which should I choose: Legend World(knights) or Darkness Dragon world (purgatory knights)/@comment-25207523-20141010175244/@comment-24965906-20141011023215

I'd say Legend, even though Excalibur, Merlin are RRR and Arthur is RR, everything else  related is R or lower. Plus like Hellstorm said, Purgatory Knights are next set, which means it could be fairly expensive or fairly cheap.

I don't have the experience of actually buying cards for real decks, however I have seen prices for real cards and stuff. So this might not be accurate. Hope I helped.