Very Messy Installers.
Had a central vacuum system installed that required minimal work since the home was pre-plumbed for a central vac. However the installers left a mess from drilling holes and cutting PVC pipe that took me almost an hour to clean up. To top it off they dripped PVC glue all over a recently painted cement floor in the basement and on a desk in the store room.
Don't use these guys unless you like a mess and permanent damage.