Having worked at a farm, I know that having a pump can be very beneficial. My former boss used to have problems with his water supply, so he decided to buy a water pump, but a small one at first. It totally failed him (and to think he wanted to save money!)...so he finally decided to buy one of those commercial pumps. Sure, it costs more but in the long run it worked wonders for the farm animals as well as the farm's root crops. It was trouble free, too.
Lesson learned: don't hesitate to buy the best that you can get; the service it gives back will be the best that you can get, too. :)