The term for the conditions that @Tropical_Willie and @rojo refer to is “duty cycle”. If you have a sump that fills frequently, then you want a pump with the highest rated duty cycle that you can find (and afford). Quality isn’t cheap. Higher horsepower also means that the pump will have more capacity to perform its mission quickly (assuming that the output piping and drainage conditions allow), and turn off again.
In addition, you need to be certain of the pump’s required installation. Some sump pumps are meant to be submerged and some aren’t. If you buy and install a non-submerged pump (or if it become submerged, like my first one did, because of a power failure), then whether it lasts very long after that may be pure coincidence. Again, a submersible pump will generally be more expensive – and probably substantially so – compared to a non-submerged pump, because of the water-tightness that is required.