I'll back up my claim that JP accuracy has suffered with my experience. Before I do that, I have to say I was (and still am) a JP fanboy. Virtually every rifle I own uses an SCS, JP BCG, and JP Handguard. I love most of their products, and I'm a big fan of John the person and his entire organization.
I own 4 JP rifles, 3 in .223 and one in 9mm. One of the .223's is very good. It took about 3x as much work to come up with a good load for it compared to several WOA barreled rifles I own, but once that was complete it's been a fantastic rifle. It's basically a 1/2 minute gun. It's dead reliable and the fit and finish was superb. It's perhaps the best rifle I own. The 9mm is also good. It's shooting into 2" at 100 with a red dot.
The other two .223 rifles suck for accuracy. On both I went to great lengths to try to work up loads that would work in them. Great lengths. Many bullets and powders tested, several emails back and forth with John Paul, etc. In both, the best accuracy I could manage was about 1 1/4 minute. The newest one (14.5" barrel, pinned brake) was so bad I sent it back to JP. They re-barreled it at their expense. The new barrel shot exactly the same as the original. I did some side by side comparison testing against a WOA barreled rifle I put together years ago that has probably 3K rounds down it. I put approximately 10 different loads through both guns, some handloads, some factory. The groups from the WOA were consistently 1/2 the size of the groups from the JP. I finally gave up about 6 months ago and rebarreled it with a Bartlien that the guys at Compass Lake spun up for me.
In addition, a shooting buddy here bought a Valk upper from them about 18 months ago. I'm not as familiar with the details of his story, but the trajectory is the same. He's rebarreling it after sending it back to JP.
I love JP and I hope they solve their problems, but I won't buy another until I have some confidence that they have figured out how to make accurate barrels again. Disclaimer #1: My last barrel from them was about a year ago. The situation may be different now. Disclaimer #2: It's entirely possible I had a run of bad luck with them that is not representative of others' experience. Take from my experience what you will.