I'm not so certain I like them.
My first burrow was a tiny little one that I made to force my masons to create a block out of a certain stone. This worked well until I forgot to remove the burrow and the mason nearly starved to death.
The second burrow was a very big one that I made for my forge operators. Since the magma is 150 Z-Levels down, people were getting tired halfway down the stairs and gave up on going down there, so I tried to force the forge operators at the very least to stay there. I made a couple stockpiles down there for food and booze, and they were OK for a while. Then one of them grabbed a barrel of booze, downed it, and started generating a billion errors about not being able to get to his destination. I un-assigned him from the burrow, and he ran up 150 Z-Levels to put the booze into the main stockpile and not in the one down in his burrow.
Later, I assigned my legendary armorer to a room down in the burrow. This resulted in about TWO billion errors about how whiny he was about not being able to store owned item.
Then a weaponsmith had a fey mood. I had all the materials but he very nearly went insane becasue they weren't in the burrow with him.
I'm not so certain I like the burrows anymore
But I don't see a better way for my forge dwarves who have to be in excess of 150 tiles away from the rest of my fort =/