It seems like having the client be in control is more common in the YUI world. That is, I think rich internet applications that talk to a server that just serves up data is more common in YUI than in jQuery. I think that's true of Dojo too.
I've seen some applications that only request data from the server and build the entire UI using DOM functionality. I've heard that this approach is painful, heavy, and occasionally very frustrating.
I've read the documentation for MochiKit, Dojo, YUI, and jQuery at various times over the years, and I've even read a couple books on Ajax. However, I've never read anything that gave a comprehensive break down of the pluses and minuses of each of these approaches.
I think most people pick an approach without even really thinking about it and never think about alternatives. Have you ever taken one approach and switched to another?