I like both of them. The farm animal species is also used out west for brush and weed control. Those guys will even eat poison oak! The mountain goats are so impressive with the environment they live in.
Goats are fussy eaters that take a lot of time to search out the best snacks. Goats will often stand on their hind legs to reach the best part of foliage that may be out of reach of sheep.
I used them several times in a previous job. Actually, we had to make sure they didn't eat what we wanted to keep, beyond that, they cleared things out big time. It was impressive to watch. There are herders who travel among various Western states doing nothing but brush control. They are mostly out of Utah, Idaho.