I too enjoy the dialogue but am not going to get bogged down in the soap box. Some of what you're asking for, such as evidence of the NFL's written consent, is downright silly. Assuming arguendo that they exist, how would I or anyone else have access to the contracts between the NFL or an NFL team with PFF? Again, that's just silly.
What I originally said is that they are credible. All of the evidence we have points to backing that point.
cred·i·ble ('kredəb(ə)l)
adjective
1. able to be believed; convincing.
2. capable of persuading people that something will happen or be successful.
The main stream media consistently sites to them; major media personnel, broadcasters, player and agent testimonials have been published on their website. That alone is enough evidence to show credibility.
I've been a longtime subscriber to their service. When they changed their business model in the last year, they posted an article on their site stating that 19 NFL teams used their services. After the change, the website was completely restructured which is why I can't point to where that statement is currently located or where those testimonials are.
However, I did get this statement in an email from Trey Cassidy today: "We currently provide data to 24 NFL teams as well as a number of websites and other media outlets."
Unless you have evidence that they are outright lying, I think you should give up your argument and step down from your soapbox. The issue of whether they are credible or not is not even debatable.
But I'm sure you'll continue to debate it and I look forward to you debunking Mr. Cassidy's statement. I would eagerly love to review any evidence that debunks that statement as long as it's based on something more than your experience and your view of how the world
should work.