Having experience with small parts in both China and US, the Chinese were more consistent.

The main difference is communication. Chinese machinists will go straight to standard, but they always hit the callouts on my parts. They demonstrated my errors. Once i improved and communicated better i never had a problem with them.

US machinists can 'fill in the blanks' and compensate for bad/incomplete communication. That led to my poor habits. But going back to them for some parts that required US manufacture I've had them miss direct callouts and require remanufacture or touch ups.

Time and money. I'd rather pay less and spend 2 more hours checking and rechecking rather than days or weeks and $$$ on reman.