This is a hard book to rate. There some great pieces to it (his working through Hebrews 6 for example). There were also a lot of things that weren't great. Much of his stance begins in a dispensational and pretribulational mindset that informs and skews his views. In the first few chapters there is an almost condescending attitude for those who hold any different views. Olsen tries to sound like he is unbiased, but his views distort his picture and direction of this book.
"Beyond" Calvinism and Arminianism is probably 85% attacking full 5 point Calvinism and maybe 15% halfheartedly swiping at Arminianism.
It would have been a better book if he had simply been fair in its critiques and not hamfisted in his dislike of Calvinism.
If you are far along in your faith and have begun reexamining what you think is true about God's sovereignty, man's choice, and how they can go hand in hand, this book has been so helpful. I would consider it a study book, not a light read in any way. I found myself reading 3 pages and then thinking about them for days before picking it up again. It examines the Scripture well and breaks down arguments for Calvinism and for Armenianism. Definitely one I will keep on my shelf.