PTO Stump Grinders? Who has one?

[squarpeg]

I am considering buying a PTO stump grinder. Would like to hear any comments or brand recommendations from anyone owning one. My tractor is 21hp to the PTO. Looked at number of videos they seem to be something I would love. Only concern I have is I am in VT land of a million rocks. Seems there is always a rock in the way of your chain saw blade.  All the videos you watch on the stump grinders are from places it seems rocks do not exsist.  That is one of the big questions.

[nybhh]

Following this closely.  I've had my eyes on the Woodlnd Mills grinder for a couple of years now.