I actually had a interesting situation 2yrs ago when i started playing at the pool halls, i went and bought a 12pack of RED masters chalk, cuz i wanted to be different and so nobody would steal my chalk.
Well you could always tell which table i had been on, because there would be lil red streaks on the table, and after a couple days of this, the owner asked me nicely to not use the chalk anymore and he even gave me replacement chalk if i gave him my red chalk, which i did.
But i would say the red chalk has probably the same consistancy as the blue. The only one i have heard of that is really off on consistancy is the light green.
I think the color is just personal preference, and that they all hold the same but you can see it better so you know when to chalk more, or rechalk.
dave