Happy is a subjective term. We've been with Verizon for years and are happy with the service. The service however does not come cheap. We've called them multiple times over the years and they do try to do all they can to accommodate us. We've been told that we are VIP customers. I guess when you're spending upward to $200 per month, you earn some sort of status with them.
Seriously though, I don't think this is a 1 size fits all question. Talk to people in your area and see which company offers the best service for your area. While Verizon is the best in my area (never had a dropped call here yet), it may not be the best fit for you.
If you're talking landline phones, disregard my entire post.