Two weeks ago I posted a reference to Don Box's thoughts on when to use ASMX, ES or Remoting. Although Don's post included references to several other people, including Rocky Lhotka, Rocky has just come back with another, more extensive posting, outlining his thoughts on the subject. A good read.
Rocky is a real smart and nice guy, who knows his stuff. I don't always agree with him on some issues, but I always enjoy reading/discussing with him and I always learn something new or gain a new insight.