See, this is what amazes me...I never had these problems on the bikes that I worked on. Only two comebacks in a decade. If it was the bikes, it would happen to everyone, but it's not because I saw huge numbers of bikes going out and performing flawlessly.
The two most common things that lead to unreliability were aftermarket parts and flat-rate-only shops that put profit over performance.
It's worth noting that even among all shops, flat-rate or not, I've yet to see a shop that had lots of comebacks that drug tested...