Too many unhappy customers. Axles that don't fit right, that make noise, break too easily, etc. There's a thread at NASIOC with a number of grumpy (former) customers. Not just random voices from the internet either - it's Kartboy, Rallispec, Turn In Concepts, DS1...
The final straw was when I stumbled on a thread from a guy who posted a pic of his stock axle next to the DSS version... The ABS ring was missing, but DSS insisted that their axle was correct and refused to do anything about it.
And my fears are compounded by the fact that these would be their very first spec B axles (as of the time I talked with them... it's been about a year now). I don't want to be a guinea pig for a company that doesn't stand behind their work.