I'll jump on the "don't waste your time and money" bandwagon. FCDs do work but so do other brands of crimp dies. The secret in any crimp die is getting them adjusted properly. The real proof is on the target, over a chronograph, and cycling in the gun.
My Dillon crimp dies do a great job crimping what ever I load. They function flawless, group tight, and have very tight max velocity spreads.
A few years ago, I bought FCDs in 38/357, 45 ACP, 45 Colt, and 44 Mag. I tested the loads over a chronograph and on paper then compared them with my Dillon crimps. FCDs didn't fare as well as my Dillon crimp dies, especially when it came to max velocity spreads.