4 year customer. Five9 is simple yet robust, meeting most of our needs.
Robust reporting, simple agent interface, no expensive software or equipment required, very supportive and available customer service. Quickly Scaleable. Great for small, medium, and large call centers.
Agent script requires HTML to write and is only one page. If call flow can be complicated, this is a problem. Dynamic scripting is a need for us as we grow, so this is becoming a problem. If a feature does not exist, if you put in a feature request. It is highly unlikely that they will develop the future you need though. We have experienced 3-5 service outages over there almost 4 years we have used them. This has lost us money. If they had a good interface for texting, emailing, and chatting with customers, that would be nice as well.