I have 3 of Serious Tool Works gouges, 1 large scraper and two of their Cam-Lock handles. I am a real fan of the cam-lock handles, and the gouges do have a flute milled the entire length, which does allow for 2 different grinds if one wants that, or the same grind, which is quick and easy to swap ends when a grind gets to the place it need sharpening.
The tool steel is proprietary to Serious, and they do not reveal what it is, but it is hard and holds a great edge. I have and use Thompson lathe gouges, and have several other makes as well.....Sorby, Crown, Pinnacle kryogenic [made by Crown] and Serious. In my opinion, the Serious is pretty much on par with other makes. Their "ultimate gouge" is 12" long and has the best edge holding abilities, and their regular M-2 steel holds a good edge as well, but the Ultimate gouge hardness is somewhere between 68-70 on the Rockwell scale, which makes it a pretty long lasting edge.
I used one of the Ultimate gouges a week ago when turning a calabash bowl at a club demo...........I never had to take it to the grinder for resharpening for the entire bowl. I use CBN wheels to grind with and they work great on the Serious gouges, probably better IMO than the white aluminum oxide wheels. Norton 3x wheels do well on them also.
Scott Trumbo has been to our club on several occasions and demo'ed twice.......several of our turners use his tools and seem to like them just fine.