great question, I have used spray attractants ever since Fish Formula came out over 20 years ago. I only use one kind now. It is the Yum LPT shad formula. It is a purplish liquid in a pump spray. For many year I swore by the Berkley Power formula but have proven to myself and several friends that nthe LPT is superior.
Sprays work better in cold water than they do warm and are most effective on lures that are slower and stay in the strike zone longer. Jigs and plastic are a natural for the spray becuase they concentrate the scent in a given area, Some sprays are masking(Garlic) other contain feeding pheramones(spelling) both are good at masking Lserine which occurs in human skin oil and is highly offensive to bass.
YUM is a pheromone based scent that uses manufactured live prey scent mimicing to both hide human scent and add attracting scent.
Invest in a bottle and try it the next time you are fishing a C rig or T rig you may be surprised. Fish2win