I thought the holding call was ticky tack, but he was trying to hold and drew a quick flag. You can tell from his body language that he knew it, no dispute.
I want to say for the record I highly endorse PFF. They have a terrific product and they have greatly shortened the amount of time it takes to recognize outstanding offensive line play with the relativity metrics they offer.
I'd say 95% of the time PFF and I (broadly) agree on grading, but we have definitional differences:
1) I put more weight on pass blocking, since those plays have significantly more leverage (impact on win/loss probability). The worst score you can get for a run block is -2, but it's -6 for a sack allowed. PFF scores a -2 to +2 for each play, but keeps separate pass and run blocking scores, which is good. That breaks down when combining into a single score.
2) I divide out all events to fractional responsibility. So if there was 1 sack allowed, I can give 2 players 1/6 and 1 player 2/3, but the fractions have to sum to 1. Unless they have changed their methods in the last 2 seasons, PFF will charge 2 players with a full sack allowed on the same play. Both systems have their merits and I'll often reference that when 2 tackles on opposite sides allow their assignments to reach the QB simultaneously.
3) I charge a lineman for a batted pass by his assignment. Some of those can be avoided by keeping the opponent engaged, so I think it's the better method. PFF doesn't charge a lineman for that.
4) PFF is more lenient with proximity pressure, but I'm tight when a lineman stays square with his assignment, but gets backed up into the area the QB needs to step into his throw. Over the years, I've been in contact with the PFF folks 1-2 times per season and they are absolutely great about taking the time to respond to reasoning for scoring on plays. These proximity pressures are usually a component of differences.
5) My charges for penalties are, effectively, higher than theirs. I charge -3 for every 5 yards, which means a single holding call will drop a tackle a full grade level and a center by about 1.5 grade levels. I've been thinking about reducing the charge for penalties to -2 per 5 yards, which would mean a hold is -4 relative to -6 for a sack (seems more reasonable), but have not done so yet. Because PFF uses a cumulative scoring system, it's more difficult to see the impact of penalties and there is a quote in the "best players at each position" article that minimizes the importance of Yanda's 2 fouls Sunday.
The other game I can recall where PFF and I had a big difference was Osemele's first game at guard vs. the Colts in the 2012 WC game. He had an outstanding set of run blocks in that game for which I gave extra credit and it was one of only 3 A+ grades I gave all season (requires adjusted 1.00 points/play). When I originally looked at PFF's scoring they had him scored negatively.
In the case of the Ravens, I think it's both fun and useful to make your own judgments about the players on a block-by-block basis. But even if you have the time to do that, there is no substitute for the relativity framework offered by PFF for the rest of the league.