I've used IO and I'm using RC right now. I did have some cyano when I was using IO but I'm not exactly sure it was the IO that caused it, since it was most likely a combination of several different factors.
It's your preference on what you use. I like RC, but the only salts I've used are IO and RC.
I've heard people mixing IO and Oceanic 50/50 to get balanced ca, since oceanic usually has high ca and instant ocean usually has low ca so it evens the two out.