Having just extracted an injection moulding tool (my property) out of china, and having paid off a number of completely shameless gangsters on the way, I would never use china for a key component which cannot be realistically designed-out.
By all means use them for
- bare PCBs
- overmoulded cables
- machined parts
- connectors
- mouldings (big risk there - see above - because they have you by the balls with the tooling cost)
and similar stuff where another supplier can be readily found, and the parts are cheap enough that you can buy a large quantity and buy it rarely, say once a year.
There are still downsides e.g.
- have to pay up front (you are powerless if there is any dispute, and many chinese companies
do play on that)
- long shipping time with sea freight (30 days; plays havoc with your cash flow because you basically have to pay 3 months earlier than locally)
- a rapidly increasing % of businesses are run by gangsters
- their IT security is lousy, so e.g. you get regular "new bank details enclosed" emails (probably inside jobs) - we lost $2k not long ago
- rapid employee turnover
- probably only 1 person in the factory speaks English, and is replaced every few months
- departing employees tend to steal their customer database; see IT fraud above, and you get contacted by other companies quickly (JLCPCB get this a fair bit)
- unless you visit (few do; it is difficult) you really know nothing about the company, which could be at a totally different address
- if you do have to visit, or try to organise a local person to visit, you often find they are not there (website address is fake)
- the parts are very often made by somebody else, whose identity will be either secret or fake
and things are getting worse each month. I used to build whole products out there but stopped that a few years ago. Too regular vanishing acts, losing the stock, tooling, test equipment, each time, sometimes offered back to us for purchase a year later by the management who escaped to Taiwan before getting killed (not kidding) for unpaid wages.
They are very religious. The name of their god is US DOLLAR