salts: IO or KENT?

[fresh]

I am about to buy a new bucket of salt, and wanted to know which one you guys consider better?

I have read that most people use IO because it is cheaper, but since J&L is selling them both for the same price, I thought I should ask.

which one of the two does better in buffering PH?

thanks all

fresh

p.s. I use IO right now.