I have an opinion!
The Double Coin tires are fine. I had a set of 19.5's on the fronts and they lasted for 36,000 miles just fine. No worse than the other brands I've used. The ride was fine too. They were very inexpensive so I was happy with the mileage I got from them. I did check the company out and they've been in business since the 1930's and have a good rep in Europe for their truck tire lines.
The stories you've probably heard about Chinese tires generally came from the OEM versions of tires used on trailers (I don't recall the brand, but pretty sure it wasn't Double Coin). And yeah, those were junk (I think they've fixed that issue now).