This blog post argues so, but I have my doubts since the author works at a graduate program whose S-rankings are much better than its R-rankings. I have a feeling that R-rankings do capture some things that S-rankings don't capture. Professors who are far ahead of their time, for example, might be recognized as such, but I would expect that their papers probably won't get very high citation counts for some time.
No, both rankings are basically nonsense. Even if you agree with the NRC's choice of a single "quality" model across all intellectual disciplines, the rankings are based on horrendously incomplete and incorrect data. This is especially true in computer science.
Also, the claim in the blog post is an obvious joke. The S-rankings are "better" because writer's home department's S-ranking was better than its R-ranking.