Either one works. The float might be easier to install seeing your just piggybacking the electrical and can be installed basicly anywhere in the bildge you can get to. With the float it's 1 wire from the battery 1 wire tied into the existing power wire, now it will work from float or switch, but might not feedback to a light on the switch if you even have it. The benifit to installing an all in one pump is if you t into in the hose rather than replace your existing pump, you will have 2 pumps incase on water and 1 fails. But it might be hard to access the hose to t into