We have been using Comm100 for a long time now, It works well as a chat system, It has Iphone/Android and desktop option, so you wont miss a chat. However, It does not automatically create a ticket in case the chat is offline, Which we feel is needed so that we can actively monitor cases as well respond to them on-time.
You can see the Comm100 live in action at our /http://philwebhosting.net
Any recommendation is appreciated. Our requirement is that it should have at least IOS/Android options for our on-the-go sales and tech guys. It should integrate with CMS or basic HTML. It should do auto ticketing with WHMCS.. and is not that expensive (Free alternative is a good option).