AMD's QA is bad. My friend runs a company that churns about >400 computers per month with AS guarantee mostly for office use. The ratio of initial failure confirmed by manufacturers was 15:1 and the ratio of failing within 2 years (cpu and motherboard failure) was 4:1. Those numbers does not reflect the fact that Intel systems sold more than AMD systems.
People dealing with professional softwares also have problems that are magically solved when they use Intel. Have no statistics on that tho.