Re: "Tracer" MPPT controllers from China
The pix of the Blixt on that URL shows the polarity of the battery terminals as being opposite of the adjacent terminals for input/output, a good opportunity for something to slip and get sparky.
Unlike Genasun, who gang "same with same" to make sure that doesn't happen.
Judging the book by it's cover, perhaps. Or, noticing one engineering team paid more attention to their product than the other.