This commentary on Exodus by Duane Garrett is one of the best commentaries on Exodus I have read. He takes a conservative approach to most of the questions and issues surrounding Exodus, but does so in a thoroughly scholarly way.
He does not old to the JEDP theory, and believes that Moses wrote Exodus during the 40 years of wandering in the Wilderness.
The commentary also contains good discussions about the historicity of the exodus events, as well as the locations of the Red Sea crossing and Mt. Sinai.