Rob, I have used editdrop a few times. Like you I have an aphotofolio website and it is free, which made it the obvious choice for me. It works very well. Each user/client gets their own account, and you can grant them access to individual "shoots" or galleries. Your clients can then select and comment on images (as can you), and you can link to the high-res versions for final delivery. The selection/commenting functions are great for communication with your client. Due to their in-built licensing module, photoshelter is more useful if you are selling images through the web. But for client image selection and delivery editdrop is a great solution. And it is free.