Fonality is a great, cloud based, full featured PBX solution
Fonality has been great to deal with. They have been flexible when needed, and ultimately have dealt with all of our issues.
We run Fonality entirely 'in the cloud' via IP phones. This enables us to setup offices whenever, and wherever we need. All we need is an internet connection. Same goes for administration, it can all be done remotely (I am the primary admin and not local to 95% of the company)
I gave 4 stars to features because it's not as feature rich as some of it's significantly more expensive competitors (IE - Cisco). Perhaps the premised based system has more features
I also rated the CS 4 out of 5. Ultimately, every issue we've encountered has been resolved. However, sometimes it's been difficult to get the balling rolling. I'm attributing this to the fact they are growing in the online space, and perhaps need a few more front line folks.