Thin front sights allow for a very crisp view within the rear sight. The half-moon shape supposedly shows you if the barrel is canted up or down, as opposed to perfectly horizontal. It also clears the holster with less snagging than, for example, a Partridge sight (thin, straight squared post). This last is most likely why it was selected.
Based on personal experience, it sucks in low/no light situations. It forces you to slow down and aquire a "good" sight picture as opposed to an "adequate" one.
Full moon clips rule. Half moon clips suck, but nowhere as badly as 1/3-moon clips.
http://splodetv.com/fast-revolver-reloadIf God kills a kitten every time someone calls a magazine a clip, what does He do when someone calls a moon clip a speed loader? It must be horrendous.
You can stack 2 moon clips in the pouch used for a speed loader. The first one is easy to grab. Use your pinky finger to "stab" the inner hole and pull up the one in the bottom of the pouch. The Blade Tech "pouch"
http://www.blade-tech.com/Double-Moon-Clip-Pouch-pr-885.html works well and you can adjust the tightness of the grip on the cartridge with a heat gun - just go slowly and wear gloves if you are tightening the grip.
All of that aside, moon clips are fantastic for finding your fired brass.
stay safe.