That's one of the problems with wanting a particular product, but realizing you might be getting more bang for your buck on a different thing. You would be questioning your decision for a long, long time if you were not completely at ease with your decision to purchase before you sent the check. It puts you in a dilemma, for sure. The only way out is to compare them side by side with your rear end in the driver's seat, make your pro and con list for both and put them to the test. I know it is painful. I had to do the same thing. Fortunately, I was able to sit on a Power Trac and see it operate before I made my decision to eliminate my other choices of tractors. I really can't help you here, as I have no experience with any of the larger models. All I can tell you about is my personal experiences.
As for the pulling power, it is a lot different than a tractor with high and low ranges. Here's why(in my simlified view of things).
A conventional tractor has an engine that powers a transmission, that powers a range box, that powers the differential, that powerss the axle that turns the tires. If we hold the engine at constant speed, put the thing in high gear in high range, off we go zooming down the road at 15MPH. But if we try to push into a dirt pile in high gear in high range, the thing goes blahhhh and dies. Not enough torque to do the job. So we flip to medium range and now we can go down the road at 7.5MPH, we can push into the dirt pile a little, but it really strains and won't push so well. So, we put it in low range and our top speed is only 3.75 MPH, but we push that old dirt pile right over the wife's flowers. Oops. /forums/images/graemlins/tongue.gif
The PT has no range selector. It won't pull a stump out of the ground at idle. It also won't go down the road at 15MPH. It is, however, set for a happy medium for the majority of jobs that it is designed to do. As Paul said, if you barely step on the pedal, that is where you get maximum torque to the wheels. As you increase the pedal, you get more speed, but less torque. To compare, you would have to get a conventional tractor of equal weight, traction etc... and test them side by side. My guess(and it is only a guess) is that the PT will outwork a conventional tractor of equal proportions on most jobs. But without the low, low gearing, if you tied them tail to tail, the conventional tractor will probably pull the PT around the barnyard a time or two. I'd like to see that. Wouldn't you?