Everyone I've spoken with has passed radbio and physics (n=5), but I also haven't actively pursued the issue with the other residents I know. I personally thought that physics was harder than what I expected, and radbio much easier. Apparently the scoring from previous years gave a quartile rank of your performance on each test, but on this year's exam, it was merely "passed" or not. According to the ABR website, last year 95% and 98% passed physics and radbio respectively.
http://www.theabr.org/RO_Pri_Score.htm