If you want to sell on American Amazon, and found a supplier at a super competitive price, but most of previous customers are from developing countries, then this one will not be a good option. Because U.S. customers on Amazon are likely to be unsatisfied with the quality, then request for refunds.
Most Chinese suppliers have their certain scope of countries or regions that they are mainly selling and exporting to. You can tell if the supplier can provide proper quality for your market simply by learning what countries they have successfully exported to.
Also, you may need product compliance certifications (sometimes mandatory) for importing certain kinds of products. In these cases, you’d better find a supplier exported to that country before, so you can use their certifications or enquire them about how to import legally.
Some developing countries have tedious customs clearance procedures, or seldom freight forwarder companies providing door-to-door delivery service.
For these two scenarios, I also recommend buying from suppliers who have exported to your country before, because they can probably refer the right freight forwarders to help you handle the shipping and customs clearance in your target country.