If you equate HP to price it becomes clear why you might want the highest weight per dollar ratio. This would be best for situations where maximum tractive force is the primary concern and the travel speed while pulling that much force is not a concern. For example creeping through the woods pulling heavy logs.
If you want high force and higher travel speed, you need both high weight and high HP. For things like pulling a big plow through a lot of acres per day.
If you want to perform some kind of high power PTO operation but don't need a lot of traction for tasks like mowing or perhaps tilling, then you want HP but you don't need the weight. In some cases, you can't tolerate the weight because it destroys the turf or compacts the soil too much.
If the axle ratings are high enough, you can generally add weight in the form of ballast to a lighter machine. Its tough to remove weight below the un-ballasted base weight of a heavier machine.
A high HP, low weight machine with the axle ratings to handle being ballasted to the desired weight (traction) when needed will provide the most all-around versatility.
But remember, ballast usually costs money too. It can be cheap if its fluid in the tires or a concrete block, or expensive if its cast iron suitcases.
- Rick