Nginx stable or mainline for production server

Hello, i know its sound ok to go with stable version for production use. but for nginx its quite confusing even from their own documentation. this is what they say on a recent blog post

We generally recommend using the mainline branch. This is where we commit all new features, performance improvements, and enhancements. We actively test and QA the mainline branch, so it’s arguably more stable than the “stable” branch.

so i want to know which version u guy’s usually prefer when installing nginx for a production server? i must add, im not that expert in server management but i wouldn’t mind updating nginx regularly whenever the update is released.

one last thing, i know i can add stable version to apt-get repository by following command,

sudo add-apt-repository ppa:nginx/stable

but what would be the case for mainline version? and does ubuntu’s default repository updates almost as frequent as nginx releases a mainline branch?

thanks in advance.