The S9s are much more stable today than when they first came out. I think that the reliability is also holding stronger as well.
I beg to differ. In my experience its pretty much the same or worse than I expected. Most of my batch 4 S9's are chugging away perfectly, while 30% of the recently received 13.5 th/s units were either DOA or had bad chains within 2 weeks of receipt. The experience is similar with most of my friends who also mine....