the pics that gobigurl posted are pics of a mantis shrimp and not a pistol shrimp!!!
I am a bit confused as to who has what
Anyhow, pistol shrimp good, mantis shrimp bad (or good, depending on what you want your tank to be!).
I had a mantis before, and my friend kept 2 big ones, and they are a fascinating animal as long as you keep them alone. They will kill everything else in the tank sooner or later. They are EXTREMELY aggressive.
What I had noticed though is the sound they make while digging is very similar to the sound the pistol shrimp makes while firing up his gun!!!
just my $0.02
Fresh.