I had one of these cheap gennies - bought second hand. It broke down
But before it did, I had run it for several hours. At the end of 25m of extn cord, it wasn't particularly noisy unless, I guess, someone wants to just hear the crickets. Certainly didn't disrupt conversations.
The output that I looked at via a scope was pretty sloppy (no pure sine wave here!) but that might have been a symptom of the impending break down!
If you can afford it, I'd suggest spending more money (2 or 3 times more?) on a quality quiet Honda generator. Should be much quieter and much more reliable.