In a new project, adding text (of any font (including system fonts)) makes render time shoot up much higher than expected, almost to unusable levels. Animation on the text increases this more.
I have another project with an mp4, a solid, and a text layer. Without the text layer, the composition renders in less time than its length. With text, the composition is rendering at around 10x-50x its length. For example, a 2 minute video with text is taking an hour to render. Render previews are kind of a nightmare with text.