Both Liberty pumps are very dependable. The difference is the GPH between the 1/3HP and the 1/2HP model. If you are concerned that you need a little more pumping capacity, go with the 1/2HP model. If you live in a very low water table location and flooding is almost non-existent, but you do want some protection, go with the 1/3HP 237 model. The only time you need to be concerned about burning out your pump prematurely is when you may only need a 1/3HP pump and you install a 3/4HP or 1HP pump. Bigger is NOT better when it comes to sump pumps.