Absolutely essential plugin. Adds a ton of functionality lacking in base OBS Studio for adding subtle polish and creating effects that would otherwise be awkwardly obtuse to implement, if not impossible. Should probably be included with the base OBS download.
If you don't install the newest version of a plugin, OBS becomes unusable, it doesn't actually respond to any of your mouse clicks or button prompts, so you have to choice but delete plugin completely or update manually. Tested on 0.9.1, 0.9.2 works fine. Awful design choice.