It has a pretty cool interface, and allows push notifications on your iPhone (all new messages can be delivered automatically to your phone and you will be notified of this). The main disadvantage is that an account at Meebo must be made, but this task takes no more that one minute. And this has, of course, to be made only once.
So, give it a try. Search for "Meebo" in the App Store or download via your PC/Mac by clicking here.
Update: Here's a video (sorry for low resolution):