Like others say, I've found the first 8-10 (in PM&R) to be fairly accurate in terms of I'd say those are the top PM&R programs (not necessarily the same order). After that you start seeing programs that don't belong as high up and programs that belong much higher up. As stated, the surveys were conducted/distributed in a pretty biased and limited manner, and surveys in general will be quite biased, so while most people in most fields will agree that programs X, Y, and Z all belong in the top 10, a lot of other programs will have pretty skewed results, one way or another.
I would just ignore the rankings. Maybe it helps if you have no idea how to narrow down programs, but I was able to do that pretty efficiently by talking with my mentors, others in the field, and looking at programs' curricula, geographical location, etc. Then I interviewed and I chose places that were the best training/atmosphere for me, and not what would impress other doctors. I matched to my "best fit." Is it the best? No. Certainly a hidden gem. And I wouldn't go to any program listed higher than it is (or lower for that matter).