Followed this advice. Definitely helped me out by not being a noob with a 30-min Battlefury. Thanks, now I can feel competent. I also followed Amra's advice of not starting Battlefury if I know I won't finish it by 15 minutes, and despite feeding early to Bristleback/Sand King tagteam, I managed to carry the team late after Axe and Earth Spirit carried early. \o/
Recovery Battlefury isn't bad, and can still be substantial. Pretty much the same reason for Recovery Midas.
There's only 2 things to consider if you're going for it:
1. Parts you have.
If you got a good farm from lane, and already have some parts of the fury(not just one), but was somehow ganked multiple times, or the lane just got hard for you to continue. You have a choice to sway away from the build entirely, sell the parts, or continue the fury in either another time(build core first, even if you have the Battlefury parts. Try to clash with team, and build the Fury even after 20 mins if you have the money, just before 25 mins.) if you can, or go straight for a recovery(before 20 mins).
2. Current Situation of the game.
If you think you can still shoot for a recovery Battlefury before 20 mins, and know you can and need the farm, then go for it. This is only viable if your enemy doesn't push out nor gank much, or if you know the situation of your team vs them can handle making space for you for the late game.
Recovery Battlefury is good since it still is before the mid-game, where you'll be needing so much farm. Since you're shooting for late game, fury gives you the increased GPM, since you're practically clearing your jungle with ease. Just don't try to build it if you really can't...From my experience, PA is one of the slowest farming hard carries in the game.
I had loads of matches where I built 18-19 min Fury. Still managed to catch up to a fully early free-farmed enemy carry.
This is one of those.
http://www.dotabuff.com/matches/1068639927