When getting started, my first bowl gouge was homemade from a piece of 5/8" diameter 4340. A 4" grinder with the wheel on edge made a U shaped flute about 2" long. Quenched and tempered and watch out bowl blanks, here it comes.
It did not take too long before the short edge life was tiresome, and I bought a HSS Benjamens Best 5/8" bowl gouge. Fingernail grind. I hated that gouge from the start. It did stay sharp longer than the 4340, but the V flute was just that, almost an acute V in the bottom of the flute. Clogged easily, and the bevel was almost 1/2" wide in some areas. Absolutely hated it.
Looking for U flutes pretty much turned up only two suppliers, and one of them is 10% vanadium, cryogenic treated. Since my first gouge was a U flute, it was love at first bite with the Thompson 5/8" U flute. Stayed sharp longer than the 4340, and the flute shape was better than my homemade.
The Benjamens Best has since been reground to work the inside bottom of deeper bowls, and it does OK there with the addition of a longer handle. I touch up the edge before each use, so edge life is not something that I can compare.
I have seen other Benjamens Best 5/8" bowl gouges, and the flute shapes seem to vary from one gouge to the other. The one I ended up with had the worst (IMO) flute shape. Maybe the shape of the flute is hit and miss also.
I do have one Oneway 5/8" bowl gouge, but it is in the rack on the less often used lathe, and doesn't see much use. I do think that it is a good tool. Although is it a V flute, it has a generous enough radius in the bottom of the V that it doesn't clog often.
