The average stats in Pathfinder don't seem to be much different than in 3.5, but on a lark I decided to look at the maximum values compared to the averages. In 3.5, at a given CR you can see a really big variance in HP, AC and saves from monster to monster, that's one of the reasons the CR system has been so widely panned, depending on what monster you pick, you may get steamrollered by the PCs or inflict a TPK. Pathfinder seems to have reduced the variance, meaning that at the same CR the monster should pose a comparable challenge, that is with the massive caveat of not paying mind to (Su)s and (SLA)s.
One thing I noticed while looking at the data, both versions have a relatively straight HP and AC trend. I always though that HP spiked at level 10 and began to increase at a faster rate, but at least in the OGL material that doesn't seem to be the case. Also while Fortitude tends to be the highest save and progress the fastest, I was surprised to see that Reflex tend to average high than Will.