http://www.autogeekonline.net/forum/showthread.php?t=99091
There is a post comparing them. I did it on my phone and didnt do it as in dept as i would of liked.
The griots is a better machine hands down.
I said it once ill say it again you can grow into the griots as with the pc you grow out of.
The griots doesnt have a little bit more power it has a substantial ammount of more power.
Speed 1-3 on the pc is identical and only speed 4-6 can fix paint.
On the griots each speed increases and speed 1 can fix paint lol.
Speed 3 on the griots is like speed 5 on the pc, not to mention at a higher speed the griots vibrates less.
And the griots comes with a lifetime guarantee, not that porter cables arent bullet proof in there own right, but if you ever do have to service it, you have to pay shipping and the cost to fix. (Average 60-80$)
I choose the griots 10 times out of 10.
I have a boat load of polishers, and i still love to use the griots 6 inch in every correction i do, it is a beast of a machine.