We have a britax (I can't remember if it's the marathon or boulevard) It's big but i know it is safe. It will last a long time also, I think up to 65 lbs. we have a jeep cherokee and the backseat isn't that big. it was a tight squeeze for the front passenger when it was in the rear facing position. Now that we are forward facing there is plenty of room again. My son loves his seat- I do too!