I've read all three. All are good resources but I recommend picking up a couple, or all three rather than relying on one.
PM&R Oral Boards Made Easy: 20 Oral Board Practice Cases (green book): Great foundation for initial studying for the boards. Solid cases, both basic and advanced. Neat thought process.
Physical Medicine and Rehabilitation Review for the Oral Boards: 17 Cases to Cover your Bases (orange book): Least number of cases, but very easy to read. Some might prefer this format-with cases and answers spread out.
Physical Medicine and Rehabilitation Oral Board Review: Interactive Case (also orange book): Tons of high-yield cases, many different authors. Has pictures- unique! Focused format.
I also tried the Qbank. Cases at times esoteric in the qbank. Preferred the books.
Use multiple resources + a review book + get a study partner if you can.