I had a tiger pistol and yellow watchman for a while. They are awesome and I was sad to see mine go. I would still have them, but I had to choose between a very nice brain coral that had to be on the sand bed and the sand dumping shrimp. I bought the coral and sold the shrimp and his attendant goby. The clicking isn't a constant issue and you probably won't hear it outside of the room. Your pumps probably make more noise. The bigger issues are:
1) Pistol shrimp need a substantial sand bed 1"+ deep to be happy. Not only must you provide said sand bed, but realize that they will tirelessly rearrange every inch of it. They also like small rubble pieces to shim up tunnel walls.
2) Because of the endless remodeling the shrimp will do you need to ensure that your rock work is secure and resting on the tank floor, otherwise the shrimp can undermine the sand it is resting on and you will have an avalanche of rock work and corals. A friend lost a beautiful montipora in such an incident.
3) Also the shrimp don't care what they throw the excavated sand on, so put all corals or other non mobile invertebrates 6+ inches up from the sand bed. Otherwise they are likely to get dumped on. For the same reason I also wouldn't recommend very fine sand beds. Fine sand could get carried around the tank by the water flow once tossed. This would be why I had to sell mine.
4) Be aware that pistol shrimp are predatory. They will eat any reef janitors that live in or on the sand bed. This creates a possible issue with detritus and nutrient control. Be prepared to deal with it through manual vacuuming, a good filter and skimmer and a refugium/algae scrubber/carbon dosing.
