Garrett turbos and put them in kits. The one exception is the journal bearing 525, which is very similar to the JWT 500. I have heard some stories about premature failure of the seals (common with a "rebuilt" CHRA which it essentially is) but others who have been luckier seem to really like the Z1 525.
Perhaps you dont approve of the way they modify the turbos, and quality control may not be the same standard as JWT but that has nothing to do with turbo design.