I personally have had many brushless motors from china, and used them in my r/c planes/ cars ..over the past 10 years...and I never had one of those brushless motors malfunction or burn up..UNLESS..it was due to error or my part....

with the chinese brushless hub motors, I would imagine there are some reports of problems , but for the most part, they should be reliable if used properly. Perhaps after years of use, some of the magnets inside the hub may come loose, but that can be repaired.