I don't think you will go far wrong with the bargain level carbide cutters.I haven't even seen an HSS router cutter in twenty years or so although I suspect I have one at the back of a drawer.One thing to watch out for is that not all the TCT cutters have inserts all the way to the centre and consequently won't plunge cut.I bought a few of these myself and it doesn't actually cause many problems as I have the option of a ramp entry tot he cut.As for the holy grail,that has to be Poly Crystalline Diamond and really needs to be experienced once you are confident the cut won't go through a clamp or worse a high tensile bolt head-but if spotted in time and with a control that adjusts feed speed you may be able to machine a nice flat on the edge of the bolt head-not that I'm admitting anything.....