There is no software learning curve, so people are up and making diagrams in minutes.
We have a central repository of documents now, and people can easily search and find the things they need.
Our clients are impressed and continue to work with us thanks to the collaboration features. When you mention to a client that you have Lucidchart, they are actually impressed (and almost always have it themselves).
We now use Lucidchart to display technical plans to staff. Before this, we did not plan to this level. Lucidchart has been instrumental in solving that problem. By bringing it into our workflow we have improved our events and the work environment for those tasked with doing the work.
Our sales proposals are much easier to understand for our clients with drawn plans included that show what it is that we are selling them. Because we sell technical solutions, we need to make sure that we are explaining these solutions in ways that they can understand. Lucidchart has made this quick and easy.
Lucidchart helps us quickly realize ideas and determine if there is value in a concept or not. Many times we will quickly visualize an idea or project and, through that visualization, realize it is not going to work/needs more resources/is too complex for the moment.
There is no negative investment impact unless you simply do not use it. Otherwise, from the moment you purchase and create a new LC document or convert a VSD document, you will quickly realize your investment and then some.
I can't comment on ROI as that's not really measurable in my environment and usage of Lucidchart, but I can say it's greatly increased my speed in creating documents like this for use with colleagues over whiteboarding, pen & paper, and other illustration applications.