We have used ClickDesk since 2014 as the main communication tool to support visitors to our website. It has been used by our sales team to provide faster and more objective support to our customers and leads, including information about our products and services.
Very easy to deploy and use (cloud). No need of training (just a quick explanation) for the users. The product may be used by anyone. It does not demand any kind of technical knowledge by the agents. A simple orientation is enough and the person can start using it very quickly.
It has an interesting log engine that sends all the conversations that happened via email for a manager.
It offers interesting option to customize colours and images of the agent, even in the free version.
It suits well any kind of website where it is interesting to provide instantaneous support for visitors / leads. It is important to evaluate how the product works when the scenario includes many visitors at the same time (simultaneous) - it will demand several agents and may increase licensing costs. We also see the product as a good option for portals or systems that may demand this kind of communication channel and simply do not have this mechanism natively.