I am thinking of replacing my son's soon to be outgrown Britax roundabout with a radian, but I am not a huge fan of how it tightens rf. Is there another, skinny low-profile seat out there? I like the Britax bigger seats, but I hate how high up they are. It is too hard for my toddler to climb in it. What would you rec? Also, is it true that the new Diono has issues as a booster?