I've nothing against them. Nothing for them either.
For me, the best use is to fit a stock that already has an uber-big channel that I don't want "as much" weight as a varmint/sendero steel would have.
After using one, I learned if overall light weight is what you want, you want light contour steel. 20" carbon to 22" #1 (with a smaller bore) saved about 1/2 a pound.
Not for me either,but perhaps viable for some. Light done right,has NO equal. Hint................
