D.W.
We have the Cosco Alpha Omega and its great! We love that you dont have to rethread the belt everytime an adjustment is needed(when they grow and need to move the belt). Its easy! And its pretty affordable. Only thing is that its doesnt allow us to keep him in a 5 point harness when he passes the 40 pound mark. I am NOT going to put my child in a boosters so this will require us to buy another seat.
We are going to be buying either the Britax Regent or the Radian 80. The both can be used as a 5 point harness seat until they are, I think, 80 pounds. One of them might be more. I want to keep my son in a 5-point haness as long as possible due to safety reasons! The only thing is with these seats, they are forward facing only. I hope this info helps!