I caught the County Line brand subsoiler on sale at TSC for about $149. I just looked and the current price is $349, more than double what I paid. I needed to cut a trench through hard clay/rocky soil for a water line to my new shop. That would have taken a week to do by hand, using pick-axe and shovel. 10 minutes I had the cut made, an hour later, it was cleaned out and I was laying pipe in it.
Folks saying you need weight on it are completely wrong, unless you put it on the tractor backward. The angle of the chisel point will make it hog right down into the soil as deep as you want to let it go and WILL stall a LX2610SU if you let it go deep enough. It'll sink all the way to the bottom of the 3-point lift travel in a few feet. I did it just to see and that almost left me with a subsoiler for a lawn ornament. It was hard to get it back out because I apparently hooked it under a rather large rock. Multiple passes work wonderfully to make the trench as wide as you want. I have a stump bucket in combination with the subsoiler that I use if I do a ditching project for diverting water in my yard on a temporary basis until I figure out what I need to do for drainage. Those two together are also an inexpensive option for small to medium stump removal too. The subsoiler will happily break roots and hook small stumps to pull them right out of the ground. It saves some hard pushing and digging that's necessary on larger stumps and may completely eliminate the need for pulling on them with chains. YMMV. I won't claim I do pretty work with it, but it sure makes the manual part of the landscaping a lot easier if you can actually move the clay.
To my untrained eye, it looks like the middle buster and subsoiler have a different angle for the point. In the TSC website photos, the subsoiler chisel appears to be tilted on a much steeper angle. But looking at them at the store, I could barely detect any difference in the frame. The only reason I can think it would be is that the subsoiler chisel is designed to go deeper and doesn't have near the cross section of the buster. A buster is going to put a lot more force on that frame than a chisel point simply because it's a lot wider. The plowshare is probably going to be the weakest point of the buster. Like some say, maybe get the buster and make your own chisel point from a piece of 1/2" x 3" steel bar stock or truck spring. I'm already considering some specialty points to go on mine.
For the price, the subsoiler is going to be a lot more useful than you think. Check around for used stuff. A good subsoiler is next to impossible to break or bend. No rotating parts. The only maintenance points are the pins and the chisel point itself. The chisel point can actually be reversed or replaced with something like a piece of truck spring.
