Apparently, who actually makes the Adorama paper is a top secret.... A rep only said it's European. I know it's not Ilford.
Another thing I didn't like about Arista RC was that it tended to separate quite easily. 5 minutes in water caused edges to come apart. I had no issues with tonality. I have to packages of 25 left. You can have one for shipping if you really want to try it. (it's RC though)