Solid product, performs well, one gripe - Meprolight Flip-Up Front & Rear Tritium Sight Set w/4 Rear Dots

These night sights work well for low-light and darkness. They're accurate, well built, and the visibility is good. Yes, they're not neon dayglo bright, but that's fine. The rear sight is a bit dimmer than the front, and that's good for a couple reasons.
1) you don't need too much brightness when your eye is right on a sight
2) it helps you tell which sight you're looking at. Multiple dots get confusing in the dark, so having the difference made between brightness levels is a smart choice.

I actually like that these aren't spring activated. It's one less thing to fail.

The only negative to these that I can point out is that the front post illumination is about a quarter of an inch down the post. This can mess up your accuracy in the dark. I modified my zero to account for it (placing the top of the glow dot just beneath my intended target at 42 yards (I use a custom zero that puts me within 4" from 5-180 yards). It has come to work well.