Interesting question, and a bit off topic on my part.
My recent brush with PEEK has me reeling at both price and the limited configurations of sheet and plate stock available.
I have a customer that I build aluminum RF housings for, and one in particular needed a cover; the original looked to be machined out of Ultem 1000 (black). I ended up printing some samples on my Form 2 out of High Temp, and these were tested, and my opinion was that they were too brittle to meet service life. There were also some covers printed out of Ultem, but these were not all that impressive, and were quite expensive as well.
The customer decided that we would be better off with Ultem, so I ended up machining these, though I wonder if a short fiber glass (similar to Rigid) version of High Temp would have worked.
At any rate, I found a “reasonably” priced source for Ultem, but the only PEEK that I ever machined was for a medical company, some 20 years ago.
I haven’t tried this, but I have interest in taking the printed part for say, Rigid, which I just received last week, and “painting” it with some, thinned, leftover Tough or Flexible, and post curing it under UV, just to give it a bit more impact resistance. Interestingly enough, I would see a similar finishing process as useful for Fuse 1 parts, to improve cosmetics of the surface, rather than a paint.