I know of several guys who have used it with great sucess. I tried it once, used the butter flavored type, and wasn't real impressed. It worked, but it left me with some clean up work. The release agent that comes with the Brownell's kit works best from what I've seen.
I asked this question awhile back on several forums and the most popular choice was Johnson's Paste wax, which BTW is used by MacMillan. PAM was mentioned as were several others, including shoe polish. One comment I've heard about the "blue goo" that Brownell's provides in their kit is that it creates excessive space between steel and stock due to thickness when cured. I could not testify as to the results on high precision machinery but it has worked for me in the past. My rifles are not what I would call Precision Tools as they shoot only in the .5"+ range. It does cure much thicker than wax though and there could be some merit to the claim.