I shoot sillywets, and I got a beautiful low-serial # Contender with an octagonal .22 barrel from a guy that swore he couldn't hit the broad side of a barn with it. (He couldn't.) He traded me the WHOLE GUN for a 10" Bull .22 which he put on a different frame and proceeded to continue to shoot just as poorly as before. Me on the other hand, got the best shooting .22 I've ever had, and started shooting the highest scores on SmallBore and Field Pistol of my life. I've heard some say they like the added weight of the bull barrel for competitive shooting, but I'm guessing that the Octagonal .22 weighs about as much as anyone really needs or wants.
Lots of cheap used Octagonal barrels out there too, in all kinds of fun calibers.