I am not sure what either one cost, as I bought both tractors used. My B 1750 has a Sims cab with a metal roof and glass windshield and plastic sides and back which are removed for summer. This works well as the top provides some shade and the air flows through well with the sides off. The L4330 has a Curtis cab with a flip open glass windshield and a metal top. Like the Sims, the doors and rear curtain come off for summer.
The down side is you have to put the doors and curtains in a safe place where you won't run them through with something sharp or pile things on top of them. Both are functional, but the Curtis is a little more rugged.