I have not had any Double Stuff offspring myself as he was never collected to Canada. I have seen some very good Double Stuff daughters, which one would expect from several thousand calves born. What I do find interesting is that when you look on the ASA website and search his daughters, there doesn't seen to be very many registered, and there are even less that have progeny that were registered. There are a few with one or two calves registered and that is it. This could be explained by his offspring being used in clubby operations more than in purebred breeding programs, but for a few years the show ring was dominated by Double Stuff offspring. His being a double carrier,probably eliminated more than a few, from many herds as well.
I have also heard from numerous people that Stuff daughters were not the most fertile creatures on the planet. I used a grand son of Double Stuff( he was sired by Double Vision), on my commercial black cows for a few years, and he sired some excellent calves here. I have posted his picture before on here and I will attach it again. His name was HC Street Legal 90N. He was out of one of our best milking donors so his daughters have made good milking maternal cows. Right now I am also using a great grandson of Double Stuff, on my commercial cows and he is also siring some very nice calves. He is a son of X Ray Vision and he is out of another of our donors. I have posted his picture as well. Both these bulls were free of TH and PHA.
Even though some of the Double Stuff progeny may not have been the most fertile, or productive , some good things can appear when his genetics are blended with others. This is one good reason that you shouldn't put all descendants of a line in the same basket and call them all bad. This is hardly ever true.