I had a 940 several years ago, after two trips to S&W the extraction problems still weren't fixed, and I didn't feel like I should have to carry a mallet at work to be able to reload my BUG, so they made it good by trading me a new 642 for the 940.

I also think moon clips are good in theory, not so good in practice. They can get bent rather easily, and this ties the gun up badly when it happens.