A suspension lift is always better in the long run, it improves ground clearance, suspension travel, ride, and flex. I t will always be more expensive if done right, but the benefits outweigh the cost in comparison. A body lift will be cheaper, and will only allow you to put a larger diameter tire on by putting space between the axle and the top of the fender opening.
Many people get away with a little of both, a low cost body and suspension lift and get double the height, but unless the actual suspension components are changed the vehicle will be no more capable off road than it was before.