Moon clips are one of those very personal preferences and each person feels their choice is the best. Most try different ones and make a decision before they buy in quantity. That would be my suggestion, so I haven't helped you there.
But I can recommend the most commonly considered best loader shown in post #5 here:
http://smith-wessonforum.com/s-w-hand-ejectors-1896-1961/476806-bmt-mooner.html
And many prefer their own design.
The GI clips are as good a steel as any, and best price usually but of course only 1/2 moon, thx to the government shippers. Here's some history you might find interesting:
The ‘half-moon’ clip evolved from a ‘full-moon’ clip design originally invented by S&W for rimmed cartridges in their ‘Top Break’ #3 revolvers in the latter part of the 19th century as a form of what we know today as a ‘speed loader’. The original intended use was never put into production however. Probably because Smith didn’t have much luck obtaining Army contracts for their revolver. A good idea languished for 30 years or so until the “The .45 Hand Ejector U.S. Army - Model 1917” was designed to chamber the 45 ACP rimless round. Why then did Smith & Wesson invent and patent the half-moon clip?
Very simple as it turns out; the military correctly concluded that pre-loaded half-moon clips could be packaged much more efficiently than pre-loaded full-moon clips. Which Smith, at the request of the Army allowed Colt to also use free of charge. Alas, the full-moon clip was once again relegated to the back burner of firearms ingenuity. Only in the more recent past, after 100 + years since its invention, has the currently popular full-moon clip finally gained its full due.
The half-moon clip was patented in 1918 (application filed August 15, 1917) by Joseph H. Wesson, one of Daniel B. Wesson's sons, who also designed a machine to load them. He designed various full-moon clips and even a quick loading carrier for 24 cartridges.
The delivery system to the US Army :
Now I'll admit I've switched over to 45 AR like Kinman above in my DA S&Ws for fun shooting. Ironically however, the most current use I have for moon clips is for my Ruger single action 45 convertible as a speed loader! Swapping cylinders with preloaded clipped 45 ACP or 45 Colt is much faster than individually unloading and reloading separate rounds in serious social situations.
The clips are slightly modified S&W size moon clips which work perfectly in the mid size single action Ruger frame.
I've shaved both the 45 Colt cyl and 45 ACP to work with clips. Either round still works w/o clips by headspacing on the chamber shoulder instead of the rim. 45 AR also work in either cylinder as well. Ironically, using the full moon clips on 45 Colt is almost exactly what S&W originally intended over 130 years ago.
