If you are going to use it for hunting, doing work, the 700 is the only way to go. Remember, these are the same engine/transmissions used in the atv's. A complaint with the atv guys is the 550 does not have enough low end and is lacking power ang get up and go speed. The Prowler is much heavier than our atv's so I would say you would not be happy with the 550. Go with the 700, you will be completely satisfied that way.