Even though Bubbl.us has a flash interface, it was much faster than either Gliffy or Flowcharts.com. The Bubbl.us interface was also more intuitive and therefore easier to learn. Ok, mind maps are not the same as flow charts, but I still think Bubl.us was easier to learn. This said, Gliffy offered more options and different types of charts while Bubbl.us focused very much on just doing mind maps.
It was also very easy to save and embed the mind map it into a blog as an image file, (see the following mind map which captured some Sunday morning thoughts on library trends). Bubbl.us however, also gives you the option to embed a script into your blog.
So does Bubbl.us have an ongoing role? - possibly, but it also depends on the quality of thoughts and intent of the mind map. This blogger has seen some pretty poorly thought out mind maps that only demonstrate a lack of understanding and unclear directions. Why is it that some of the worst managers love mind maps? Maybe it is because mind maps are so easy to do, it looks like the participants are planning and scoping a project when in fact they are just making a big mess. In these cases no amount of good software can help. :-)
Learning 2.1: Flow charts and mind maps