Howdy Treekiwi,
Heres a short video of the grinder my mate uses, he's doing the stump from the tree i felled in my video.
Its a Red Roo, he has done some pretty big stumps for me and it seems to work quite well, as well as being reliable.
This is his second machine, the only fault he could pick was that the handbrake is a bit flimsy and wears out too quickly.
Heres the link as well.
Good luck.
RED ROO - Commercial Outdoor Power Equipment