Huy Fong brand sriracha is based, and originally popular, in California. It has a distinctive flavor; every other competitor I've tried has been too vinegary or too sweet (your tastes may vary, of course). So I can absolutely believe the stories in the article.
I haven't tried Underwood yet. It's made by their original pepper supplier (Huy Fong switched in 2016), but I hear it's a bit different.
I've since switched to Underwood Ranch and the flavor I remember from 5 years ago is back.
I now buy it by the case to save on shipping and distribute to friends.
[0]https://www.mashed.com/182079/the-real-reason-huy-fong-srira...
Edit: The "new" Huy Fong sauce has a very distasteful aftertaste to me - I kept thinking I had some old/bad bottles that had been laying around the pantry too long, but brand new dated from the store also had the same thing. I likely am in the minority here, but it was enough to stop using sriracha at all until I came across that article and had a chance to order some Underwood. Now it's back in the rotation for me.
If I can't get Underwood there are plenty of boutique hot sauce brands now that have acceptable versions. Yellowbird is quite popular and available, but I find it too sweet for my tastes.
I've switched to Texas Pete brand. They are very similar, and I can't describe why I like it better exactly. More 'peppery' and less sweet, if that makes any sense.