There are artists and music preferences vary according to the public, and historically the Rock and Pop have been controversial among themselves. On the one hand the Rock is a musical genre that was consolidated for being a protest movement.
And pop refers to music popular guy who "sold" with a plastic image, the late and early nineties. He was referring to easy songs to sell, where the image was superimposed in front of the voice and message of the songs.
While all genres that preceded it were trying to strong message to society. Currently any song can be known as Pop, because the only requirement to be Pop is that people know. That is your goal; People, Pop is not something that is purified in music, but in the image and record sales.
Many bands or artists dare to Pop to reach people and be famous, but sometimes there are bands or genres that become massive and end up being Pop.
Say which is the best kind, would be controversial, but if you have something in common Pop and Rock; is people.