We've owned 4 trailers over a span of 25 years and can say that with each new purchase, the quality of materials used have been better with each unit.
Most notable has been synthetic materials replacing wood or press board which was terrible in our older units.
Most of the issues you'll encounter will be due to the lack of QC and the haste in which these units are assembled.
Every trailer we've owned required a half day of my labor and various tools to work out all the kinks do to lack of workmanship but all good afterwards.
