My mach IV is quieter, burns less powder, the little cartridge is just plain cute and kills coyote as good as it's big brother. I can't speak to fouling because none of the three 17's I own have any fouling problems. I'm afraid that the factory offerings rem has announced (20gr Vmax) will be to explosive to give consistent results on coyotes the 20's should work on fox and cats though. To get the most out of the 17 Fireball you will need to handload the 25gr hp's for coyotes. All that being said the 17 Rem will do everything the FB will do and then some, despite that I haven't fired a round from my 17 rems in 2 years. My 17 Mach IV is just to much fun.