I've used this software in my last job and we all really liked it.
The organization and the ability on setting up the organization is a huge difference maker for IT support managing support issues and client projects. It's super easy to create and assign tickets. Zendesk also makes it possible and easy to use add-ins from third parties.
The setup takes quiet a bit of time to get the maximum use and value from it. And if you don't set up every little thing then it is not worth it. But our team had so much experience with it that it was easy after we got the hang of it.
The last job I had required us to use ZenDesk for different things. But here are a few things I have to say about it:
To communicate with our partners, contributors and clients across the studio and remote locations. It's highly recommended for all kinds of businesses, especially when someone is in a remote location. Me and my team at the time were very happy and satisfied to use it, and communicate with our contributors and clients.
I am not currently working with them but had a great experience with this software.