We rented one a few years ago when ours was down. To be honest, we were not impressed. Groundspeed is fast, and the offset wheel is a nice touch, but the grinding is
painfully slow. I knew the second I looked at the cutter wheel that it was gonna be a long day. I guess it depends on what you're used to. We've run Rayco RG50 since 2000. Some will say even thats too slow. But compared to the Rayco the Toro was a silly little toy, especially on large stumps.
Random pics I pulled off the web. Compare cutter wheel size and thickness:
Is the Toro better than nothing? Yes. Does it have good points? Yes. Would I buy one? No.
I'd recommend renting a couple of different size machines if possible. I think you'll agree very quickly that with stump grinders, horsepower is king. And nearly all the most powerful machines can still get in tight spots. All manufacturers know the importance of being less than 36" wide.
A possible compromise would be the Toro STX 38. Same machine, more power. Haven't used one, but I'll bet its a huge improvement. Not trying to knock Toro or Toro owners. Not promoting Rayco either. There are many good machines out there from several manufacturers. Just my experience and opinion.