I have one on my .223 varmint rig. The A/O is a PITA compared to Side Focus, but if your smaking gophers @ 200 yards you have the time to fine tune your scope. For any other application, I leave it a the 100 mark.
I prefer to keep my big game rifles free of A/O or SF styles, as that instant focus can mean the difference between a full freezer, or tag soup.