I did my OB rotation under Beckmann!! Weird dude - i could see how his book would be hard to read. never picked it up myself. sorry - my response isn't actually useful
That was the one textbook I actually read in all of my rotations -- it's an incredibly easy read, well-organized, and has a ton of questions in the back. For the shelf you can mostly skip the sections on gyn onc, as long as you've gotten the basics in a lecture somewhere along the way.
I thought it was a near-complete waste of time for the shelf. Questions are too detail-oriented and short, not at all like shelf questions. Poorly edited, can see the lack of updating and continuity between editions (e.g. still have questions on Norplant). Case Files was beautiful and gave me my first H on a shelf exam.
of course, if you have infinite reading time, go ahead and read both.