Yes, I saw that Art Wolfe and others are on Photoshelter. The only caveat here is that Art Wolfe doesn't need Photoshelter's name to sell his images - I would imagine that he can attract a fair amount of buyers all on his own. Photoshelter may work for him, in that it simplifies delivery and pricing of online images, but I need to Photoshelter to attract buyers - I don't have the archive that Art Wolfe does, so I'm not able to tell publications I have diverse enough coverage to be my own stock agency.
I would agree that Photoshelter's setup and gallery creation is easy for those who don't have much experience creating websites - and certainly no programming knowledge is necessary. I think it works best as a portfolio site - and if you have a core group of editors that frequent your work, then you might be able to make things more convenient for them by providing online sales - with direct delivery. I haven't seen any new people browsing in Photoshelter - my hope, and maybe this was unrealistic, was that Photoshelter would be a place where new clients would find my work.
Raymond Klass Nature Photography