Here's an update on this old thread. I have used this implement for a few years now and it has been so great I would like to strongly suggest it to others. First, I use it to rip along the edge of fields to root prune trees over the border that send roots into the fields in search of nutrients. I can see a difference in the crop.
Second is for garden use. You have to be careful there's nothing underneath but with my MX5100 or L4300 Kubota I can go 12" to 14" deep and there is a noticeable improvement in yields. More important, there is rarely any standing water in the spring and the ground dries out and warms up faster. I can get on it sooner.
Third is general farm use. One shank is not real handy because of spacing and fuel use but a three shank minimum would work like a charm. That would give a 30" spacing and with a "winged" point on it would be an acceptable spacing. With only narrow points the suggested spacing is 20".
In addition, with a bigger tractor and CATII, I have ripped out big rocks and pulled stumps I thought I would have to back hoe out. They just popped out.
Anyway, if you ever see one of these and think you might have use for one, buy it. I've only seen a couple for sale and they go fast. Single shanks sell in the $600 to $750 range used and the $850+ area new. The Deere ripper doesn't look as good as this one and I think is $1500.
Oh, the one in this thread weighs 250 lbs and is rated at 125 HP. For those who think you don't need a parking stand, you better be strong and quick because to stand it up and hook to a 3pt hitch takes a lot of multi tasking and four arms.