Pretty sure LRI sells a good solid barrel vise too (and personally I'd choose that over SAC); theirs is solid steel on steel against the barrel which is the best when you really need a lot of grip without slipping. Wood, aluminum, leather, paper, etc, even powder coating, are all sort of ok if you don't need a lot of torque, but I've run into slipping with every one of those with really tight barrel removals. A correctly sized set of steel bushings or blocks gives a lot more torque capability and won't scratch a nice barrel if your bushings have a decent finish.
Personally I make my own vise blocks with a hole ID sized specifically for the barrel I'm working on, but I know most people don't have that option. There's not really any substitute though for steel vise blocks matched to the barrel; nothing else grips better on a smooth round barrel.