I have two and like them very much. I have one for my M&P9c and a shorter one for my BG .380.
I find that now, I actually use the longer version for my BG, when I want to deep conceal. The gun will be barely noticeable, and if I had an even longer version, it would be completely hidden by my belt.
I tend to use it when I'm at some dressy-casual social function, when I'm not wearing a jacket and a cover garment would look out of place. It's not quick to access the gun that way, but I still have it with me.
The guide rod "snaps" into the barrel. You do need a belt.
They definitely serve their purpose for me. No thickness of a holster to worry about, and the gun stays secure.