I think it's all about the juice.
When I run thicker juice and/or dark or heavy VG juice through the Stardust, it's yuck. Doesn't wick well, burnt taste.
When I run a 50/50 mix through it, it's fine.
For thicker and/or VG heavy juice I use the Visions or Fluxos.
Just my limited experience. I'm happy with the Stardust, but they are a bit finicky when it comes to what liquid they prefer.
I've wondered if it isn't this way with all cartos and tanks--it depends on the juice. My stardusts work well with beverage type flavors so far, but I usually use my eGo tanks for my heavier juices. I'm really hoping these Stardusts hold up well--I really like the product.