I'm one week into my website and blog being created with Grav. I have noticed a few key things in that week.
Native 2FA authentication: Grav supports 2-Factor Authentication (2FA) right out of the box. Enabling is a simple two step process to move the slider to enable and setup the authenticator app. It's nice not to go hunting for plugin to do what should be a base function.
Decreased System Resources: I have received fewer resource alerts for my server when its running low on free memory or CPU. Serving static pages has reduced the resource footprint for normal operations.
Boring Theme: My theme is a bit boring. I am using slight modified fork of the default Quark theme. Unfortunately, it's not high on my list to change at this time. All of the major elements on my site are working so I'll keep it for now. I will eventually swap it out with a more visually appealing theme.
I've got a few other sites and projects that are still using WordPress as the rendering engine. My plan is to slowly convert those to Grav as I get free time.