As I wrote in other thread (which has been moved to the question forum)
I have never tried the mantis tiller but I haven't really seen them around here; I haven't looked for them.
I have the small Troy-Bilt 4 cycle tiller (29cc maybe) and it does what I need it to. I did have a bigger one, Huskee 190cc but it took two people to pick it up and put in the beds. I tried the Troy-Bilt 2 cycle tiller but it quit working after 10 minutes and I took it back.
