I'd go a little further, and I know this is how some people use the web, but for an anonymous poster on a board like this to basically libel two small companies with zero evidence is pretty outrageous.
At this point you'll have to wonder if your man is just a windup artist. Or just utterly clueless. Maybe it's time to start ignoring his output.
I'll add my experience with Generation whistles, which is pretty much 100% success. I bought my first examples in 1975 or 1976, but have bought a fair number since then. Most recently, I just bought some a few months ago for my grandchildren. In every single one of these purchases, I just took the first one the clerk offered (or the random one that was shipped in the recent case), I didn't try any others before purchase, just accepted what I was given. Every single one played well. Some I have come to like more than others - a D and a Bb both purchased in the 70's come to mind -but all the rest play just fine. One or two that were in good tune when new became a bit out of tune after 30-40 years and I had to slip the heads. I have tried and received as gifts other whistles over the years; I have yet to find any that I like as well as my Generations. Perhaps I am just used to them. But I have never played a bad one in 40+ years.
I am pretty certain that it is just bad luck coming across a bad one. Like I wrote, the ones that I have that are bad, all seem to have come from the same injection-mould that was worn out. And they are just bad. Not even the best breath control would change anything about that (and I consider my breath control to be just fine, having played wind instruments for 35 yrs and having owned a Generation C for 30 yrs--still have that one but the head cracked). But my goal really was not to bash them, quite the opposite. But there are (or were a few yrs back) lemons out there. And that is probably true for any make of whistles. No company has a 100% great products over decades.
My observation is the same as Mr Gumby's--the bad ones all were bought a few years ago. The last ones I bough were all good. And one of the newer ones plays even better than my vintage one. The same sweet high notes that never get piercing, and that nice chiffy sound.
