Food for thought: AmeriGlo makes a set similar to this, but the rear sight is a single dot below the front sight, similar to the Heinie sights mentioned elsewhere in this post. It's called the Pro I-Dot, and is just over half the price of the Trijicon sights. I have a set on both of my Shields. The Tritium is produced (and stamped) by Trijicon.

It's hard to tell from the product photos, but it looks like the orange ring on the AmeriGlo sights is actually brighter than the Trijicons. Mine light up even in moonlight.