Theyre Okay. They use quality materials. Not a fan of the shape its hard to keep it clean with the bell bottom shape. I would go with their cheap option i think its called the titty banger which is shaped more like a normal banger.
As far as quartz goes though i much prefer the opaque bottom quartz. I feel as if it retains more heat and stays hotter for a little longer which extends the dab. highly educated, toro and eternal quartz all make opaque bottom dishes in america
if it is import quartz the experience probably isnt any different. unless youre using an opaque banger import opaque doesnt perform nearly as well as the name brand opaque bangers if tried.
The main difference is the quality of the materials and the quality control.