I'm sure if you're looking for the rating on this seat, it's because you've heard someone say how great the seat it, how popular it is, how it's the best out there, etc. I heard those same things so I went ahead and bought two-one for each of my children.
I just might stand alone in this opinion but I have to say, I don't get the hype about this car seat. Is it comfortable? Sure. My child has never complained about any (4) of his car seats. So I don't know that this one is more comfortable. It is easy to install? Definitely not. It's heavy, large and clunky. This is NOT, I repeat, this is NOT a car seat that you will want to use if you're dropping your kid off somewhere and need to leave the car seat. You best just invest in another one for that. Is the safety ratings good? Definitely. This car seat was rated an A by the National Highway Traffic Safety Administration (nhtsa.gov). It received an A in every category, quite honestly I don't see how.
The main reason I bought this car seat was because of the safety factor and that it goes to 80lbs. It was worth the money to receive both of those. This should be the last car seat I ever have to buy.