The Chineses machines that I have that are a few years old are of reasonable quality.
These are the ones with the smaller keys.(vending tower.com)
The ones that are from a tubz vending round that I bought last year are absolute garbage!
(snack tower.com)
They have bigger (Toyvend size) keys and the locks are of inferior quality, it is so easy to strip the threads as they are loose screwing into the back bar even when they are new.

The mechs feel clunky and does not turn so smoothly and also the coin carriers are not milled out big enough too except some £1 coins.
Also noticed some of the segments are milky and that the mech handles have lots of play, even when new.
The handle tolerences are critical as if they are too slack the coin carrier moves so much that a genuine £1 coin is prohibited from turning in the carrier by the first little spring loaded finger

The companies that are offering machines of this Quality to new intrants into this Business should be ashamed of themselves!
People who try to grow a Business on equipment that is provided sub standard from new dont stand a chance.
If anyone has bought theses machines from new I reckon a call to trading standerds would be worth a try, not fit for purpose IMO!