I don't know what all these people are writing about but I've used Logitech for years since they were a small company and their customer service has always been Grade A for me.
I had a keyboard that I used for like 8-9 years and the space bar broke. I called them up and it turned out they had discontinued that keyboard a few years ago and there were none left. Instead of them saying "oh well" they actually sent in a request to see if there were any spare parts and wound up shipping me a few extra keys they had left over (including the space bar) all free of charge.
A few years later my mouse started acting up, it was out of warranty but they wound up giving me the latest model of that mouse that had replaced the one I had and again it was free.
The only time Customer Service has failed me was when I bought the Orion Spark and then a few weeks later they announced The Division sales promo of getting it free with the keyboard. Customer Service told me they couldn't get me a key for it and that I was out of luck.
Was pretty damned disappointed with that but oh well, no company is perfect.