Sorrow doesn't really seem useful, unless you're bad at crowd control.
Although I take it back, Anthem makes CC4 FB much more viable.
Quote from Azareel;1180637:
I've also noticed something peculiar. While playing Harvest Song continually (during Phantasmal Chorus, for the music), I noticed that the gathering speed bonus was randomly changing between two numbers 3 apart. The effect is reproducible. I wonder what's going on there?
If you're in a party you're probably forgetting about Harvest's party bonus.