Taste-wise, both are equal in my opinion. What puts pepper as my vote is that salt is very difficult to see as you shake it over your food, so it's hard to know for sure if you've added too much or too little. Pepper is pitch black, so that makes adding the proper amount you want a lot easier since you can see how much you've added. But maybe that's just me. I mostly put salt and pepper on just white rice, and it's almost impossible to see salt on rice.