This and increased dmg to elites are some of the best mods to get as your gear starts getting decent. People only care about sheet stats though, so they seem to ignore these.
Here's an observation I had yesterday. Basically, all shoulders in this game are shit, unless they're part of a set. If you don't have a set shoulder already, getting Aughild shoulder + helm with ring of royal g is much, much better than random lego shoulder + andariels helm if you were using ring of royal already. People are obsessed by IAS + elemental + cc on andariels, I get it. However, if you can't take advantage of the proc if you're a ranged class, then do this math - 15% elite dmg + 6% cc + 15%skill + dmg reduc set mods VS 20% element + 6%cc + x%ias on Andariels + worthless bonus on your shoulder. I find Aughilds is usually the victor, and its very easy to farm the mats and make really, really nice pieces.
(remember you need to factor in your other skill/elemental bonuses)