I like plain steel, one piece rods for the simple reason that they don't pick up grit (sand, primer residue, dirt etc.). It's essential to keep any cleaning rod from touching the muzzle crown as that, more than any other factor, will destroy the built in accuracy of the barrel. Brass and/or aluminum rods pic up dirt and grit, so I avoid them. This little bit of maintenance info I picked up at Camp Perry from the USMC Rifle Team armorer. He and the team members also used muzzle protectors described below.
I make up muzzle protectors for use with my rods from cut off bottle neck rifle cartridges. You cut off the head, then slip the brass cartridge case over your cleaning rod, allowing the cast to enter the muzzle as you brush or patch out the bore. Simple, effective in protecting this vital area from the file like wear that a cleaning rod rubbing on the crown can produce.
You select the cartridge case based on slipping it over the rod and also the case neck's ability to slip inside the crown. For instance, a .30-30 case works well with any of the .357's, .40's, or .44/45's. A 5.56mm or .223 case works well with any .30 cal. barrel if you have a skinny enough cleaning rod.
With .22's, I'm damned careful to keep the rod from touching the crown on rifle as well as hand gun.
HTH's Rod