Olark is the best chat tool hands down. It's simple to use, has a depth of features, and utilizes great features. I love the chat interface a lot, the Accepting New Chats/Not Accepting New Chats functionality is perfect. I have 4 monitors and being able to see out of the corner of my eye if I'm accepting chats is key. Your status is obvious and since I am away from desk off and on a lot not accepting chats is easy to set and easy to confirm that's my setting.
We have Olark integrated with our CRM software, Nutshell, using their available API. It allows us to talk to leads on our site and log the conversation in Nutshell simply by typing !lead when the conversation is done.
There are desktop notifications so you are notified even if you somehow have the tab hidden.
We also used some options to pull data from our web application for users that are signed in, name, email, phone are all pulled automatically and we're working on adding additional functionality.
The customization settings are very well done and easy to navigate.
I did have a dislike here but after some searching I found out what I was hoping to do was already possible! So as of now, I'm not finding anything that I currently dislike or could even hope to improve.
Sometimes you get leads on your website and they aren't the phone call or email type. Having chat is a necessary business decision and every web application needs it to provide the best customer service.
For our paying clients having chat adds more legitimacy to the system as they know help is a chatbox away and they don't need to call in.