Kitchen Blenders

I would like to make juice and had the Vita-Mix recommended to me. However, it appears to be a high powered blender and I have heard that juice shouldn't be exposed to heat or high RPM's. When I saw a video of a Vita-Mix making juice, it took about a minute and rotated really fast. It seems like this would heat up the juice and the RPM's wouldn't be good either. What are your thoughts on this?

Yes, that's the reason I didn't order one.
I just use the Breville because it isn't nearly as fast and I had the exact same worries.

i want to ground up a dozen bags full of various chinese herbs and plant matter into a fairly fine powder. Obviously I don't want to take all week doing it in a cuisinart or small blender. I've looked into leaf shredders but think it might not be fine enough. Though I don't want to spend a thousand dollars on something. Ideal would be some addaptation I couldmake to a power tool or some common gardening tool, something I could rent.

You might want to look into buying a second hand disintegrator or hammer mill used for pulverizing paper. You might be able to find these in government liquidation auctions.