I can help on half of your question. I have used a bobcat high flow stump grinder on many occassions on my T320 and have been pleased. The biggest advantage for me is mobility. You can move from stump to stump pretty quick. I can't compare it to a dedicated grinder, but I would guess that it's the same as with anything... jack of all trades is a master of none. If your main focus is going to be grinding stumps, a stand alone stump grinder would probably be more effective. For me, it's just a small part of a clear by mulching business so the attachment works good when we encounter a area full of large hardwood stumps. But, I can't be competitive to go to someones house and grind a few stumps, Not to mention they wouldn't be happy with the turf damage caused by the tracks.