We're getting the Nautilus next month. DS1 hasn't outgrown his Greco CarGo seat (he's good for a few more inches and about 35 more pounds
) but we've had it so long it is about to expire. I like that it converts to backless. I can't recall the age limit here but he's staying in a booster until the seatbelt fits correctly & given his growth so far, we have a few years to go.