We got Britax seats for both cars - great seats, my daughter loves them and have served us well. However, now that I'm expecting baby #2, I wish I had thought a bit more about the type of seat I was buying as I have a 2 year old and and 11 year old step daughter who spends every weekend with us. I'm now having to think about a new car so that the Britax, the Graco bucket seat for the next baby and an 11 year old can fit comfortably in my car (honda accord).
I've had a lot of people mention the Radian seat as it doesn't have the same side bulkiness as the Britax at the sides and is more accommodating of multiple seats in a car.
Just sharing something to think about.