I imagine most people's opinion of each shipping service is a result of the actions or inactions of the local branches, and less to do with the company as a whole.
Any company is only as good as the sum of people who work there. None of them are perfect, they all make mistakes, it's how they handle the mistakes they make. I never deal with locals, I print labels at home and drop off. I've only dealt with corporate when need be....
I used to only use UPS because they were closest to my house. I'd print labels & drop off the packages at their ship center. UPS lost several packages of mine, and has damaged a few also. I filed claims, they never paid one single claim for some BS reason or another, even after a few friendly & polite phone calls to corporate, nothing. The last straw for me was UPS lost a item that was insured for $1,500 and they would not stand behind it, it went into a sort center and never came out, gone like a fart in the wind. After I refunded the buyer his money, I had to eat it. That really irritated me.
FedEx has not been perfect. I've had to file a few claims with them also. Huge difference to me though, is FedEx has always paid on a claim. Last time I filed a claim with FedEx 4 days later there was a check in my mail box.
USPS is a joke for paying claims also. They never pay them. I will not ship anything with USPS that is worth over $100, just because of their lack of paying on a claim. $100 I will eat it, if USPS looses it, anything worth more than $100 is going FedEx.