BO1 = Great
BO2 = disappointment for me
BO3 = great googly mooglies!
BO1 was a great racer. BO2 ditched most of the traffic for chaining turbos, and I just didn't like the lack of drama, wider tracks and sloppier handling. BO3 I love. Still less traffic, but the handling is sharper, the tracks are great, and the whole battling thing is fantastic.
I think they are all different games really
BO1=Ridge Racer
BO2=Tony hawks chaining combos
BO3=Road Rash