The majority of fans/journalist have Anderson Silva as the number one.
Honestly though, "P4P" Is throw around so much today that Im starting to wonder If people really know the meaning of It anymore.
Here's how I always saw pound for pound. Imagine a magical place where every single fighter weighed exactly the same, but had all their strengths and weaknesses.
Who would win? A 200lbs GSP vs a 200lbs Silva, I would put my money on GSP 9 outta 10 times. But I would place my money on Cain 6 outta 10 times against GSP.
Therefore, all the fans/journalists are wrong and Cain is the P4P best fighter on the planet.