What do you like best?
Integration with Confluence is one of the biggest advantages.
Lines look smooth and nice.
Since is integrated in the wiki, once you update the graph it reflects in all the references to it in the page. It is much easier than created a graph locally, then uploading it, and later on modify it the same way again and again.
I like using it as a quick way of laying out ideas and brain-storming notes so people can look at it and chime in.
What do you dislike?
Limited functionality in terms of what can be done with the objects.
Not too many predesigned icons to choose from.
Sometimes, automatic connectors don't work as expected.
I some times find frustrating font sizes, and how text objects are places.
Zoomin and out is not obvious sometimes, and that can be a problem.
Recommendations to others considering the product
I totally recommend this product if you are in a situation with remote workers, but not limited to it.
It also helps if you don't want to take care of maintaining graphs living in many local computers of many employees, but instead a single graph that is source controlled as well.
I recommended considering add-on to improve the basic version of gliffy.
Being able to set a default font size and type could be useful.
I sometimes miss rounded corner objects.
What business problems are you solving with the product? What benefits have you realized?
Quickly sharing algorithm designs with colleagues and management for review.
Technical reports about finished algorithms that can be shared and edited by others.