Honestly it all depends on the person. I have had 15 Lucid dreams now and I've become lucid off of RC's 4-5 times out of those 15.

I find they don't work for me. I still use them at least a couple times a day, but I use them mainly when I'm in the dream before I do something, or just to keep my awareness in the dream.

What doesn't work for some may work beautifully for others.