I have used one since 2005. I like them because they are relatively easy to use. I taught my 6 year old son to use it, and he called in his first bull with it in 2006. He's 10 now and he used it last season to draw 3 bulls into the same canyon below us at the same time.
One thing, I noticed that every bull we have pulled in with it was a satallite bull. I can't think of a single herd bull that we have lured with it. I imagine that is probably normal (since satallite bulls are generally looking for a fight, and herd bulls are looking to protect what they've got), and I am not too concerned about it, since we have called in some bruisers. Now I just need to draw the $#@!ing tag!!

Two other guys in my camp use one too. I was thinking about getting Elknuts Chuckler because I have heard so many good things about it on this site, and I wanted a different sounding call too.