I have the matt Mettler polyester that came with the Pfaff Hummel designs. My machines like it and the colours are great.
That's good to hear. I mainly was interested in the Black, you know, if it is weaker for any reason.
If I have problems with other brands (in black as well as other colors) breaking with a design, I switch to Mettler.
As with any thread, make sure it is not old thread (or sitting in the sun) when you buy it.