I have used the Sweany and a couple of the laser types and they work OK. However, I have not done a lot of work with handguns, as most of the boresighters are designed to work with a scope. There is an Alpec laser bore sighter that is made for handguns as well as rifles, but it is fairly salty at $149 per caliber (it fits in the chamber like a cartridge).
For most handgun use, it is easier and cheaper to adjust the sights by shooting than by buying a boresighter.
Jim