My DA 17-70mm failed after about 1.5 years.
I've been using via manual focus for 1.5 years. After reading about admissions of a faulty design, I inquired of Pentax about getting it repaired. No mention of faulty design of SDM or any special discounts or replacment. They said send it in and they'll give me a quote on expenses to fix it. So, based on what I've seen, it will probably cost me $200 or more... which I'd rather spend on a reliable lens that won't fail.
Very frustrating when they know it had problems and has been proven out to be true by the landslide of failed SDM motors.
I also have a DA* 50-135mm which I've used sparingly because I'm afraid the SDM motor will fail if I use it more often... this just isn't right... I should be able to use my gear worry free. PENTAX SHOULD, so to speak, JUST BITE THE BULLET AND MAKE THIS WHOLE PROBLEM RIGHT!!!