I replaced a ~14 yo Barley Crusher with a Cereal Killer and have been very pleased with its performance.
It's a much more rugged build, has bearings instead of bushings, and the rollers are supposedly hardened.
And I was able to use my hopper extension with the new mill. Win-win.
Given it can often be found for under $90 it has to be the barley mill bargain...
Cheers!