Foremost we are dealers, not of the amps you have listed but I have come across them since we service and take trade ins. We have had a very similar Yaqin traded in and I have a few customers who have tried the others you listed. As some have said and I feel it is incredibly true, you get what you pay for. Do these amps sound bad, not at all, for $200-300 they sound like they should at that price. Cannot compare them to a $2000-4000 amp because that is not what they are. Bargain of the century, absolutely not. With that said if your looking for a small inexpensive bookshelf system and want to roll the dice, maybe.
There is so much made in China animosity which for political reasons I can understand along with safety being a concern. We rebuild many 1970s solid state units which the same attitude was there against Japanese built units then. Today many of these are prized pieces for some vintage collectors today, however many of them were junk as well back then and are forgotten.
The one piece of advise I can offer is tube amplifiers tend to sound as good as the transformers they are built with and the quality of parts in the circuit. The iron on all these amps are tiny which I've seen many fail within monthes of buying. With that saving for a better amp makes more sense. Even if Amazon reviews are truthful, they are usually written shortly after purchase. A quality tube amp should last decades, not years which is what I feel you get with these inexpensive amps.
Good luck with your audio journey!
