Both are still sources of information.
I don't rely on any one piece of information as 100% accurate. PFF has issues of course but so does @kerouac9 vaunted football Outsiders.
I use PFF as a quick reference for grading players. Keke has like a 62 grade which means he is an ok player.
69 the year before too.
Drafted the same year as Zach Allen and better by a total of 32 points on Allen over that span.
As you say, it's one source along many.