I've used Visio, Dia, OmniGraffle, and lucidchart.com. Dia is pretty terrible, sadly. OmniGraffle seems to be fading away. Lucidchart is ok, the sharing is g

I've used Visio, Dia, OmniGraffle, and lucidchart.com. Dia is pretty terrible, sadly. OmniGraffle seems to be fading away. Lucidchart is ok, the sharing is good, and the Confluence integration is widely used. Visio is kinda the best. I've even used it under WINE on macOS. I don't use UML much. I tend to do basic ER diagrams for database stuff, and higher-level "boxes and lines" otherwise.