Without any doubt the only service that manages to both have advanced features and user friendly interface.
I like the complete dashboard with useful tools like shortcut answers. I don't like that it's in flash. I would love that they use status instead of messages like olark to notify user presence in IM mode.
Very good live chat help! Love it! Works fantastic on my website!
nice design, light and powerful, zopim rocks!
Used to be on free livechat alternatives, paid for Zopim a few months back and never looked back.
i use this for my website. love it as it syncs best with my IMs.
In terms of backoffice support - the best choice available.