No. Many of their writers are from Europe so they know f*** all about the NFL. What they do is watch videos of every play and then assign a number value to each player involved, from -2 to +2. So for the Bills, let's say, if Tremaine Edmunds is supposed to plug a gap and overpursues, he gets dinged for not doing his job.
The problem, of course, is that this is subjective by its very nature. What if another guy lost his assignment and then Edmunds had to pick up the slack? What if the assumed gap he was supposed to fill wasn't actually his job? What if a receiver was supposed to cut towards the middle but cuts the other way instead and the QB throws an interception because of miscommunication? None of those things are taken into account.
The only thing they are really good for are team stats, like QB pressures and pass rush win rates. The fact that players' PFF rank is plastered all over the goddamn place on SNF because of that dipshit Chris Collinsworth really grinds my gears.
If you want useful information, Football Outsiders is far cheaper and a lot more accurate. None of those "why the f*** is this team ranked so high in this thing it looks like they are average at" like with PFF. And they have weighted stats too, to take into account strength of opposition.