We're a week into having 2 living weed eaters in our yard. Meet Mowgli (left) and Chives (right). These guys knocked out the overgrown area outside our kitchen in a week. Above you can see a semi-before and after: the left is what it looked like on day 2, the right is what it looked like after a week (and Charlie cutting down the ligustrum that was too tall for the goats to reach and/or knock down to eat).
Now we've moved them to the front yard where they'll work on English ivy and wisteria. I'm not sure how long it will take them to demolish the area, but they're already clearing it out with vigor, fertilizing as they go. That particular area will become a woodland garden with paths, hopefully being clear enough for little hands and feet to get in and explore safely.
When I was a kid we rode our bikes through the woods, jumping fallen logs and feeling "extreme". Yes, I realize just how dorky that sentence makes me sound and I'm ok with that. I just want M and F to have the same opportunity, a natural playground available for whenever they feel compelled to get out there.
If you're in the Charlotte area and are interested in renting goats, I can't recommend Wish We Had Acres enough.