i own a britax boulvard ($325+), Britax marathon (300+) and a sunshine kids XT(325+). bought the sushine kids for my son when we passed down the britax to baby bro and he begged me for his britax back because it is more comfy. love the streamlined profile of the sunshine kids, but if your kid sleeps in the car much (we do b/c we live far from town, so errand days the nap is incorporated) be warned that the sunshine kids is very upright, so if you have bucket seat to recline it will be fine, otherwise the head will flop a lot. bought the XT for extra side protection to alleviate problem, but it just doesnt work. got a marathon used and my kid is so happy. britax is the lazy boy of carseats. i get it now, after having another brand. they are so safe and so big and heavy, but the kid is comfy, which is important as we stick them in these things for years and years. also, had to put my 65lb. niece in my boulevard in a pinch and she was comfy as could be. my choice is clear. i will stick with big, bulky britax till my kid approaches 60 lbs, then switch to a very simple booster.