over all fit ,finish and std build ( making sure the bridge is straight and square, etc.)
lets be honest, fenfer build quality sucks on most instruments , even the usa ones (but their usually better). The MIJ's are some of the most consistant and best IMO. Go play 5 fenfers and see what you get, go play 5 spectors and you tell me who does the better work.
The attention to detail and quality of work on the korean spectors is some of the best on a mass produced bass imo. starting form the 80's. Stuart started them up doing quality work and showed them what was expected and exceptable. Import companies can and do do some great work, as long as they know what is expected an exceptable.
If you build a 1000 of anything you cannot help but get good at it. If you build 1000 and the quality is not up to par then either there is a major issue in the build process or you don't care that your building junk. if you build 20,000 and still have the same issues as day 1 , then you obviously have made the decision to build and sell junk.