I wouldn't want to tar all no-name ebay turbos with the same brush.
A friend of mine has a factory that rebuilds turbos, had been doing conversions for a long time, and more importantly makes precision balancing machines. He had a salesman try and sell him some Chinese made turbos, and had one with him. My friend took off the covers and tried to check the balance. He aborted the test before the turbo got up to speed as he was about to over-range his sensors. If the sample was that bad, what are the production ones like? Certainly not better, he checked one of those too.
A colleague bought a 'T70', he was happy with it, and reported the kind of engine response that didn't make sense to me, but whatever. It failed, and he brought it in for me to look at along with another smaller turbo he'd bought. When I measured the wheels the 'T70' was more like a T3/4 and the smaller turbo was actually bigger. Neither was anything like the spec he thought he had. His new Garrett seems to be holding up Ok.
When I read the adverts I see a lot of technical turboesque words that sound impressive, but don't actually make any sense.
There is no reason why China can't make brilliant turbos, but until a serious player is prepared to put their name on them I won't put them on my car.