From what I've read in other reviews, results may very, and they might depend on the color of keycaps chosen. I chose grey and black, and the lights absolutely do NOT shine through the rest of the caps; only the legends. As for the legends, not all of them are completely evenly lit, which is only expected from SA caps being as tall as they are, and its not even that noticeable, anyway. Furthermore, they are super sharp for what they are.
Unfortunately, what they are is that stenciled style that has been developed recently to allow PBT doubleshots to be possible. And these aren't even PBT caps. However, they are nicely made ABS caps, with higher quality legends and molding than the cheap PBT shine-through SA doubleshots I've tried recently. They feel great, look nice, and sound great fitted on my Kaihl Box White switches. They also didn't have an uncomfortably tight fit like the aforementioned PBT caps I tried.
All in all, I can vouch for the quality of the grey and black set. If I had to guess, I'd say that its the colored versions that probably have more issues. I've seen similar issues in other types of keycaps. However, I'm guessing the monochrome ones are fine. If you want SA shine-throughs these are probably your best option by far. My Anne Pro 2 is so much nicer with these on, and considering how nice the keycaps that came with the board were, that's saying something. But that's the power of SA for ya; just a really great form factor. It's shame that Signature Plastics don't make proper SA shine-through caps, but these definitely do the job.
Would recommend to a friend.