I'll be short.
We all know the pro/cons of Juggy.
This build is made to have a huge présence during ALL teamfight and maximum survavibility.
Dont try it if you're the main carry. You could need more dmg in late game.
Dont forget that with this build, you're unstoppable, rush straight into enemy group, activate bladefury/utli/ BKB. Fight should be finish and you should have kill and your full health bar. ;)