R.Y.
We have a Graco Nautilus and it is a really good seat for us. My son is 3 years old, 40 lbs and 40 inches. I don't think being a lower weight matters since it has a 5 point harness. This seat will keep him in a harness up to 65 lbs and then converts to a booster and backless booster (up to 100lbs). We are expecting this to last until he no longer needs a booster. There is a comparable Britax seat (with a harness not just a booster)that cost more and maybe a few more models I saw online only.