At the current rate of our customer base and limited customer support resource, Zendesk gave us the most bang for our buck without any heavy training for agent and admins. Zendesk's intelligent support team is also based in San Francisco, making it easier to just to communicate. With the module we implemented, Inbenta (semantic search for the knowledge base), it seriously lightened the load for our agents in terms of work and stress, making the customer experience overall a better experience for both parties.