I had two upgraded. Door-to-door turn-around time was just over 3 1/2 weeks for the first and just over 2 1/2 weeks for the second.
As for whether trigger quality is better or worse post upgrade, I have mixed feelings. The main difference that I can appreciate is that the trigger breaks a bit lighter on both pistols post upgrade. This is a change that might be welcomed by many, but I was one who felt the P320 trigger break was a bit too light to begin with.
In dry fire, comparing my first upgraded pistol to the non-upgraded one, I felt that the take-up on the modified trigger was a bit smoother, although no shorter or longer. The reset was also a little more positive and audible for the modified trigger. These are not differences that I can appreciate in live fire, however.
Apart from the lighter trigger pull, I felt that the quality of the break was about the same. Some have described the break as "crisp". I think they have low standards for crispness. Although I felt that the P320 had and has a good trigger break for a striker-fired pistol, I have yet to shoot a stock striker-fired pistol that did not have a break with at least some creep. The amount of creep in the P320 trigger break pre and post-upgrade seems to me to be the same.
The first time I shot my modified P320 full-size .45 ACP in live fire, I experienced a significant degree of trigger finger sting after shooting less than 20 rounds. This was outdoor shooting on a fairly cold day. The second time I shot the same pistol, I did not have any actual discomfort in the trigger finger after 30 rounds, but did have some tingling which might have gotten worse if I had continued to shoot. I also had one round fail to feed. This was Winchester white box 230 grain FMJ and the failure to feed may well have been ammo related. But I had shot plenty of the same stuff prior to the upgrade, and this was the first malfunction for that pistol.
A few other individuals have reported trigger finger sting after the upgrade. This might be more common with the .45 ACP pistol. I had never experienced the same phenomenon with the pistols before the upgrade, both of which came with the second-generation "adverse" trigger.
When I shot my modified 9 mm P320 compact I did not experience any trigger finger sting. But I did have a lot of cases ejecting straight back at my head, which this pistol had never done before. I had only done a cursory inspection of the pistol before shooting it to make sure it had been lubricated. When I got back from shooting it, I did a close inspection and cleaning. The ejector looked fine, but there was an incredible amount of gunk on the breech face and under the extractor claw. This did not look like the typical carbon powder residue. I think it was metal debris from the slide milling process. I have not yet had an opportunity to shoot that pistol again after cleaning and relubricating it. I sure hope SIG has not modified my pistol to hit me with hot brass with consistency. I already have a Gen 4 Glock 19 that will do that for me.