Frustrating part is eyes change over time, hence the ever changing prescriptions. But in my case age is also now affecting color contrast, white/blue light sensitivity, how fast eyes adjust from bright to dark settings, and I don't recall headlight glare being such an annoyance in the younger days. Blaming it on those damn high-intensity headlights tho
So, red dots & red fiber tubes use to be just fine, but now they are a bit more difficult to see. Green however really pops, is much quicker to pick up. At least for my eyeballs, everyone's different. One thing I didn't anticipate when going to a green 507C/K is having to switch the iron sights back to a red fiber tube so as to not see TWO green "dots" i.e. the green fiber sight AND the green optic dot.
I just mounted a 507K Green to my Shield Plus, and it's pretty freaking amazing. Got it zero'd in about 5 rounds at 25 yards (rested), then started shooting 25+ yard head shots on steel using just the "donut of death" (circle with no dot). Wicked fast and didn't drop a single shot. Definitely allows me to get all the accuracy out of that little gun.
Not sure if it's an improvement up close at speed, but for accuracy work it really is night and day.