I know how to look up PFF grades, so I am aware of Blankenship's grade.

I was making an off hand comment about how Ertz really had his number that day. It wasn't a tit for tat comment related to Harris.
As for Hampton was moved to LB specifically because Owens outplayed him in camp -- I am a bit of a media junkie especially during camp (I try to attend some camp, too) for everything I can listen to and never heard that one -- not doubting you on this at all but i am curious which reporter had that report because that's a juicy missed story for me. Converting someone to another position because an undrafted FA was outplaying him -- to me that's either a big time endorsement of Owens or quite the slam of Hampton.
I am not married to PFF scores but i do like it as a reference, lol, depending on who am debating, some think I love PFF too much and others not enough. But, If we are sticking with the PFF theme, Hampton had a better preseason than Owens as to the games. And I'd presume they both played in the 2nd half in the preseason games so its likely apples to apples. Not that it matters.
Not sure about camp though. In the practice I watched neither stood out. Lynell who has a show on 980-106.7 as a radio sub, recently talked about concerns about the safety spot and if I heard him right he suggested he was told to curb his enthusism about Owens, and was referencing Hoffman-Paulsen on it and the vibe I got was it was inside info. But he said it so quick, am not 100% sure that I heard it right. I know they love Owers as a special teams player. I didn't get any buzz about him this off season though from the podcasts I listen to from the beat reporters. But he certainly has the athleticsm to be a stud.
Reading Harris' PFF scores doesn't get me fired up for or against him. But when I go strictly with PFF, I do value the last season the most. Yeah the season before wasn't good for him aside from his run defense score. The season before that was decent. So on PFF scores alone, 2 of the last 3 seasons being decent is good enough for me in the context of I trust Peters with moves for veterans. He wasn't perfect last year but pretty close as to FAs. So for me, the PFF scores don't scare me or excite me.
I feel neutral staring at those PFF scores. Peters tips the balance. Logan ironically in his Q and A podcast the other day talked about in his mind the flaws with PFF grading. They were talking about how PFF has John Bates with a horrendous run blocking score -- yet Logan among others think Bates is the best blocking TE in the league. So how can they be that far apart from the PFF score. He got into it. But in short, Logan isn't the only one who likes PFF but takes some of their scores with a grain of a salt. Not saying you feel differently. I am just explaining there are limits to how literally I take PFF. I got to watch the players along with looking at the scores.
So ultimately my opinion will be formed by watching him. I just started watching the game against us with all 22. Just watched some of the first quarter so far. My initial impression is they move this dude everywhere. He was even in the middle linebacker spot on one play. And they like to use him to blitz. Not saying my take after watching him will be on the money or not. But for me, I don't get too fired up for or against players on stats and PFF scores unless there is something dramatic, otherwise I need to watch them. And lol, maybe I'll turn negative after watching him. I don't know. I don't really currently have a leaning one way or another.
And don't get me wrong I am not high on Harris. I am just not sure. I don't mind looking at PFF scores for a brief idea of the player. And when I look at it from that context, those scores are fine enough for me. Nothing that gets me excited or concerned. But when I pile on to that both Mark Bullock, and Logan Paulsen watched Harris and liking him. I don't always agree with Logan and Bullock, but they both among social media are the most avid watchers of the Commanders scheme and do breakdowns. And I would guess clearly Whitt liked him. And Quinn. And Peters. All of that for starters makes me give them the benefit of the doubt. Until i watch him.