Be careful with Oceanic. Not only is the alk low, the Ca is often TOO high at normal reefkeeping levels. From what I have understood, they make their mixture so that it's 400+ at 1.021. Since we run our reef closer to 1.026, you end up with 500+.
I use IO, not because I think it's the best salt available, but because it's universal, so you can get it anywhere. I've picked up buckets at Big Al's on special for $29 (stock up!), and I buy buckets at Petsmart for $32 by having them match their website price (print the page and take it with you). IMO, change is bad, so pick a salt you will have easy access to, and stick with it forever.