Everyone says the heavier the better. But I find my "light" GS1572 plenty heavy for grooming our crusher-run top dressing with river rock base. The GS essentially never hits the river rock. I have no trouble pulling it with 43HP, even with a large load. I believe that Land Pride specs them for 30-50HP? If you have a different surface or grading needs, YMMV. It is very well built.
I discovered that I bought the wrong size. It's important for maintaining crown that the center-of-the-road skid ride IN the center of the road. If I do this on our roads, averaging 10ft wide, the "ditch side" skid is a foot or more too far off the side of the road, not in the ditch, and just riding up on vegetation and crap that is way above where it needs to be. So this holds the plane up too high to do anything. I'm selling my new GS1572 and buying a GS1560.