I love Britax and believe the larger size, and steeper price as compared to other carseats, are well worth it.
my ten month old is still in her Chaperone very comfortably. My friend's eleven month old (who has two and a half pounds on my daugther and was moved into a convertible seat two months ago due to getting too big for her two other Graco carseats) loves to crawl into the Chaperon to sit.
I have the Chaperon in the center of the backseat of my Accent, which is not comfortable for anyone else seated in the car (because of the massive size of the Chaperone, and the Accent being a compact car), but it is manageable and the safest spot for her.
I would absolutely recommend Britax seats to everyone. I love them, and look forward to moving my daughter into an Advocate CS 70 when she reaches a year.