You can consider looking at Desk.com (based on Salesforce cloud platform) and Chatter. The same could be customized per your need and user based license system provides some definite cost advantage. The cloud based system provides the ease of accessing the same anywhere and on any device.

Looking for any specific information? Feel free to reach out.

Intercom's new real time platform looks amazing:

https://www.intercom.io/real-time-messaging

We love Intercom as it combines many of the best aspects of a Help System with an easy to use interface and gives the ability to segment users and give them semi-personalized messages based on the combination of their activity in the app and how recently they visited. Intercom supports real-time messaging too.

- Zopim by Zendesk, it's very easy to setup and use. Our team of 5 love it!
- Create a Knowledge Base for top questions will help solve chats faster.
- If you're using a Mac, A-Text is a life saver. Simply text expander but makes a world of a difference when on chat.

Happy to help with more insight!

We use a stack of:

- Intercom: Besides having a chat with the user, you have a lot of usage data from them. Also, you can create auto-messages. If they're done in the right way, they can be pretty personal.

- HelpScout docs: for knowledge base. It's a great tool for creating content and organizing it.
- Wistia: To upload videos and see how users are interacting with it
- Screencast O-Matic for screencasts: sometimes you have to show things for users, so this it's the best free option out there.
- clyp.it: For recording audios: It helps you to give more personal (if you know which language users know)
- Skype and telephone: Last but not least. To really understand customer at early stage, you should talk to them and still telephone works pretty well for that :)

It's a mix of tools who makes them to feel more personal :)