Since I work with wood and carbide is much,much harder than wood I know that any carbide will easily cope with the material.I have never yet bought a useless cutter from any source.I did find that one included in a very cheap router kit was pretty poor but it wasn't something I even realised was there.I have bought complete kits when the big sheds have a special offer and never used 70% of those included so now I look on amazon and Ebay and they have all worked.It costs three times as much to get them sharpened as they cost to buy so when they eventually get blunt I buy new.