if what your gonna do is sheetmetal.. then I highly recommend the lenox metal max..
the fiber discs work wear quickly and make a dust storm...and they get smaller od with use.the blade will wander when trying to cut a straight line.. and are prone to breaking if pinched
the lenox keeps its size and the blade is stiff enough it doesn't flex or break,, and seem to last 4ever
https://www.lenoxtools.com/pages/lenox-metalmax.aspx
I get mine at lowes