Has anybody bought or heard a Chinese knock off amplifier?

Regarding China, Mahgister is the one who knows what he's talking about. I bet most of the others have never been to China and are "experts" based on CNN. CCP enjoys huge popularity and support in China, much more than any GOP or Dem government will ever get in USA. Mistrust of China is ridiculous, how often does China send soldiers to invade another country? USA sends soldiers abroad to kill and conquer all the time.
Back on topic, if you look at the way Chinese counterfeits are made and sold you will realise they are not meant to replace the real thing and are also not meant to fool a buyer. These are for people who want to fool other people into thinking they have the real thing. Same as counterfeit bags or watches. If you want original quality you buy the real thing.

I imagine that if you live in Hong Kong or Tawian you love the CCP who will use any force necessary to control you?  I don't think so.

Short response: if it breaks or comes to you nonfunctional, will you be able to say "Oh well", and throw it away or try to fix it yourself?
Long response:
There are some really good Chinese products, but if you have an issue or your component breaks and you can't speak Chinese, forget it.  If you must buy Chinese, go through a seller in your own country.  A lot of their HIFI components are not particularly cheap, so if it breaks you are left with a paperweight/doorstop.  Even with the name products (not counterfeits) it can be difficult/impossible to get satisfaction.  I've had issues with Topping products in that I was sent a UK plug for US use and spent many weeks just trying to get the Chinese dealer to understand that I needed the US one (Shenzhen Audio didn't give me the option of picking US/UK plug, and Topping usually sends both).  Never resolved - instead of sending me the correct wall wart adapter I needed, they sent me an IEC power cord which was useless for it.  Sent pictures of what I needed, and got back polite, nonsensical responses.  Second was a Topping DAC that had the lettering on the front upside down (same seller) - they offered $20 refund for a $750 unit.  Even with a company like Denafrips, you can't return something just if you don't like it, and any repairs you need (even under warranty) after 30 days you have to pay shipping costs to send it back to them.  The Chinese knockoff guitars of famous brands are nowhere near the quality of the US models but they don't even try to pretend that they're the real deal (and they're a lot cheaper), so you know what you're getting.

Mistrust of China is ridiculous, how often does China send soldiers to invade another country?

You might like to address that question to our friends in India at this very moment.
Or pose that first part to our friends in Hong Kong and Taiwan.
Or Vietnam.
Or Thailand.
Or Cambodia.
Or any country near the South China Sea.

if you look at the way Chinese counterfeits are made and sold you will realise they are not meant to replace the real thing and are also not meant to fool a buyer. These are for people who want to fool other people into thinking they have the real thing

Going to need a second cup of tea before I can even begin to absorb that one...