I use RS macro'd in with Oblit, Blood Strike, and Plague Strike. I've found that those 3 abilities with it in #1 allows me to never miss a RS when it's up and #2 leaves enough RP for the occasional FS to toss in the mix. I use a one-disease rotation as frost, but for aoe pulls I'll toss in a PS and spread it around with Pest.

I noticed an enormous increase in my threat with the macro'd RS, despite my own observation that I "never" missed one. I clearly did, whether it was the timing of my white swings or whatever. I highly suggest macroing it to your up close and personal melee special attacks.