Convertible carseats

We are finally getting around to switching the infant carrier to a convertible carseat for NJ. We have a Graco Comfortsport that I got off of my registry but it seems that everyone else is getting a Britax Marathon/Boulevard. Should I be concerned? The B is way more expensive, but I wonder if I'm sacrificing quality by going with the Graco. What convertible carseats do you have? Any recommendations? If need be, I will look into returning the Graco and getting another one.