I won't speak for John and the unit being on his site. I'm fairly sure they're not offered anymore.
What I will say is what I was told at the 2011 MOSES conference at the Kaye Corp BCS booth. They basically said the blue Mantises were sold with the right angle tines you get from any other manufacturer, not the "Mantis" tines you get on the actual Mantis. That made them not-so-good versus a real red Mantis. They didn't sell well.
Frankly, I had both a Mantis and a MTD knockoff. In short runs (1/2 acreish) I could outdo either one with a Glaser wheel hoe. The Glaser does a better job faster with no fossil fuels, no noise, and no damage to the plants due to "rock jump". The Mantis went to a new home and the MTD is still knocking about here somewhere, but will probably never see fuel again. The Glasers are expensive, but very good. I got one at a CSA liquidation garage sale. It has the steel handles, not the wood one offered by Johnny's. There are many US made alternatives that are well built and less expensive - Valley Oak, Maxadyne, Plow Hoss are a few. They're basically the old Planet Jr.s from a century ago. Great, efficient units
