Jim Moore is a wonderful WikiTreer, but one that many others in the community probably have never met. He is impressively talented -- and thorough -- as a genealogical researcher, and he does a careful -- and beautiful -- job of documenting his research.
Jim's disambiguation study The One or Two Mathijs van Ceulens is a brilliant piece of work, conclusively debunking the widely believed assumption that said that Mathijs Jansz van Ceulen, a Dutch settler in the vicinity of modern Albany, New York, was the same person as Mathijs Abrahamsz van Ceulen, a high-ranking official of the Dutch West India Company in the Netherlands.
New Netherland is not Jim's only genealogical interest, just the area where I've interacted with him most often. Wherever I see Jim around WikiTree (I don't see Jim around here nearly as often as I would like), he is doing very thorough work or dispensing excellent advice. When Jim Moore talks, genealogists should listen. He's a wonderful WikiTreer.