dependable mixers??

I have a Kitchenaid 500 professional or something of the sort. I had to send it back a month after I got it because it shut down on a batch of pretzel dough, which is ridiculous. They sent me a new one, no problem, but seriously, that shouldn't have happened. I was livid, and it took a couple of weeks for that whole process, so I was out of a stand mixer.

Kitchenaid sure doesn't make them like they used to, and for such an expensive machine, that one especially should not have shut down on dough at a speed of 2.