I am not familiar with the 420LF, but the 430L is pretty kickin'! I took my Rex to the local heli field for the first time yesterday, and the nitro flyers were stunned at how much power I had in reserve. Anytime I punched full collective the Rex would climb like a rocket, and you could actually hear the rotor speed increase instead of bog down like many of them do, and I'm running a full 11 degrees on the top end. I am not flying 3D yet, but I'm fully satisfied that the 430L motor has all the power that will be needed when I reach that point!