I can agree with all I've read here. I have probably bought a half dozen China scoots, one from a dealer, that they never could get started. Every time it was the same problem, restricted carb jets.
The good thing about the China GY6 Honda clones is that Honda parts will fit. They are perfect copies. I rejetted them all with genuine Honda jets, one or two sizes larger and they all started and ran great. As stated above, the China materials are inferior to what the Japanese and Taiwanese use. There is not a Mainland China scooter made that comes very close to the others mentioned, but some are much better than others and their names are mentioned above.
If you are on a tight budget, and who isn't now-a-days, one of the Chinese bikes listed above might meet your needs. It helps greatly if you are mechanically inclined and do the routine maintenance
faithfully. Read everything you can about these bikes and treat them as if they were fragile, because they are.