This link connects to an article by James French, who programs computers at the University of California, Berkeley, and has written papers on general semantics and logic published in journals such as The Journal of Symbolic Logic. He presents ten thoughtful arguments against using e-prime. I found it useful while I considered whether to practice e-prime. I choose to practice it, regardless, because doing so helps me accept impermanancy, and take responsibility for the content of my statements.
http://learn-gs.org/library/etc/49-2-french.pdf