We have been very satisfied with the solution. It was very easy for people to migrate to it, then start using it. They use it to their advantage by taking advantage of some of the features that they didn't have before.
At the end of the day, it's a phone. It rings, then I pick it up and get a good signal. I don't have issues with the call, and it also gives me the flexibility to be able to get an email from somebody who I don't even know what city they are in. From a support standpoint, I like that I can go to my directory search through it, getting their extension to call them.
My utilization is to go through the PBX on a regular basis and add people, change people, etc. When we are setting up a new site, which we don't do that often, to make some changes there, we are able to change the dial plans when people come and go. I have yet to find something that we need to do that I can't do.