I can offer a single data point on Torpado, and it was memorable.
A customer for whom I was building a new frame in the '90's had a good-looking Torpado: Columbus SL tubing, chromed forks and rear dropouts, and a nice pearl paint job. It had a crack in the lower head lug which is why he was having the new frame built. He was a 130lb rider which made me wonder.
With his permission, I sectioned vertically through the head tube to discover why it cracked, and what a surprise: the miters were not even remotely shaped like the intended mating surfaces and had no points of contact, so the (pressed Prugnat S-4) lugs were left to carry all of the load. The point of greatest stress failed first, at the underside of the lug right in the crotch.
I have no idea if this was representative of the brand but it made quite an impression!
Steve Maus
Greenwood, IN USA