It can be good but it is very RNG. For progress it is almost too inconsistent to use.
I have had fights where it procs 14 times, and others where it procced 2-3 times.
If it doesn't proc, or you have to use the cancelaura macro, then is wasted and literally just agility, which is worse than the Reaver stat stick trinket.
There are some situations where it can be very powerful, e.g. if it happens to proc a few seconds before imps spawn on Xullhorac or Mannoroth, but again it is very RNG.