father in law uses the crossbow type. just got it this year he really likes it since usually on a 4wheeler. was showing me on the tip of needle though where he thinks if was extended out some would make it come out a little easier. at my dads place he uses the sticks you just ride up and poke them off of horseback with loves them he doesnt care for the gun that shoots them though never said why though. but out of the 3 or 4 people i know have them i havnt heard one person say it was a waste of money so they must be alright.
I have a CO2 powered rifle. I will only use it if for some reason I can't get an animal into the chute/headgate. It works fine for an initial treatment but if I need to give a second it's harder to get close to the cows without them walking away. I can't seem to get the darts in while they are walking; they bounce off and I can see expensive antibiotic shooting in the air.
It's nice to have but I hope I never have to use it again.