I picked up several thousand to use with plinking rifles. Forget how, but think I was out of br4s, I ended up using the SR primers getting ready for and during a local sportsman's club 100/200 yard match. Didn't Chrono them or anything but they shot just as good as br4s in my 6br at shorter range for me. Wish I would have bought a crap ton of them now, but glad I had 3 or 4 thousand of the Sr and lr on the shelf now for when my normal CCIs run out, if all this craziness is still going on.
But my usage of them, was working back to load I used checking for pressure. Once at normal load just starting shooting a bunch of groups. Hadn't shot in a while so spent a couple of days shooting about 200 practice shots, then about 40 or 50 at the match. Had my Chrono with me during the practice but since it was shooting just as well as it had been with the bench rest primers didn't even worry about it. I wouldn't hesitate to buy them if I could find them for reasonable prices (although $120 seems like the going rate on all sites I have seen primers in stock on, don't think that counts as "reasonable", so i wouldn't buy them, or any others, for that price.)
Granted this is not an extremely large data set, nor recorded with traditional methods, just my thoughts and experience. Have used them with other rifles/cartridges and haven't had one fail to fire or delay ignition as someone else mentioned, I do however hate the cold weather, so probably had almost ideal scenarios each time I pulled the trigger behind one of their primers.