i think it's a matter of preference and legalities. when i lived in the sates, i carried both and often left the handgun(ruger .44 mag) at camp due to the weight and packed my spray during the day. up here in canada, not legal to pack a handgun, so we carry the spray, never once needed either. had more than my share of close encounters with griz, blackies, cougars, bobs, even nutcase squirrels.
although, i have used the spray while camping with my family. on a couple drunk punks who were harrasing my sis-in-law. the didn't take kindly to me "manhandling" them off of her in the brush and one of them pulled a knife. they didn't like me after the spray.