I bought a jetglo 4003 almost exactly a year ago. The bass plays beautifully and i have had no quality control issues.
I have played bass for about 22 years and before buying this bass, I played only a single pickup 1995 EBMM Sterling for 20 years. Unless you started out on a Rick, you will definitely have to get used to this bass.
I went through a bezel and a zero mod thumbrest and numerous tonal settings before finding what I liked. It took a month of solid playing just to transfer my muscle memory over to this bass, i believe due to its slightly smaller scale (33.25). It took about 8 months to find my tone. I ultimately went with the zero mod thumb rest. For the band i am in, i like the bridge pickup with an open tone.
The action is amazing, love the look and tone. The bass is not a one trick pony as some have stated. If you are used to a Fender-style bass, it will take some time to truly bond with this bass. It is very much worth it. My bass playing has improved, i can play faster and with more precision than before.