Otie wrote:
I think ratings have more to do with the ability to take an extra base than actual speed. Many players make poor choices of when to run and get thrown out despite their speed, while others who lack speed know when or when not to run.


Yes. From Bill James Online, per James's Baserunning Analysis,


"... a player's BR Gain (or Loss if a negative number) is the total of all the types of extra baserunning advances minus the (triple) penalty for all the BR Outs compared with what would be expected based on the MLB averages. Zero is average. Plus numbers are above average and negative numbers are below average."
Under this analysis, the Top 10 MLB players in Baserunning (BR) Gain for 2009 ranged from +19 to +27 (Ryan Braun). Andrus was a -6 BR Loss in 2009, which could explain his poor runner rating in DMB. Andrus did, however, have excellent numbers in James's SB (Stolen Base) Gain in 2009.

While I've never found James's site to be the cat's pajamas (especially considering all the great free online sites), I think I'm getting at least my money's worth ($3 per month) from his Statistics section.