Dalton and Dagon were both idiots who brought their people nothing but misery and death.
Quellon was a very forward-thinking man who should have not listened to his son about invading the Reach during Robert’s Rebellion. Vickon Greyjoy was also sensible politician.
Many of the Hoare Kings – Horgan Hoare, who allowed religious toleration, Harmund the Host who spread literacy and education, or Harmund the Haggler who built alliances with the Lannisters, Hightowers, and Gardeners, Harmund the Handsome, who tried to end reaving and thralldom, Harwyn Hoare who made the Ironborn rich by seeking trade and avoiding war – actually left the Iron Islands better than when they started, or at least tried.