With complex diagrams, you'll quickly get a total mess and if you are lucky to manage how to get finalized nice diagram then any tiny element added later will ruin the whole diagram since puml decided to reposition everything. Another limitation of puml we faced: there is no way to control the position and layout of elements on diagrams. We realized it's just impossible to handle in a reasonable way hundreds of diagrams from different teams who have to show/maintain cross-component dependencies independently. I'm in an automotive project and we had tried to jump from Enterprise Architect to the puml and the latter one failed very quickly. PlantUML is a nice tool for small diagrams/teams/projects but it doesn't scale to big projects at all. Since these events, I have avoided Notepad++ entirely and been reluctant to use Plant UML, but used it out of necessity. It makes me think: 'What are they going to put into it next? Malware? Perhaps watermark the output with a statement?' But in my mind, if the developers of these programs can be so influenced as to push this onto their unsuspecting users, I feel they have misused my trust.

On startup, Notepad++ would write (literally type it out) some message into the default empty document. This is similar to what the Notepad++ developer(s) did back in 2013-ish where they had a memorial build into a new release of the program. However, for every error generating a diagram, Plant UML would show a popup window with a picture and a text in memory of that person. If they had just added a memorial section in the program, it would have been fine.

While this attack was undoubtedly a horrible event, I still feel it is deeply unprofessional to include stuff like that in a program, and it makes me lose all trust in the developers. About 3-4 years ago, my local install started showing memorial plaques for people who died in a terrorist attack in Paris. However, I have one major gripe with Plant UML. Anything that can help me draw less figures is a bonus and the markup language they use is pretty flexible and ergonomic.

I have used Plant UML a lot and I love it.

Open source uml editors