Well, if you are some kind of openssl master, acme-tiny is flawless.

In practice, for most people, reserve a few hours for your first deployment. After you got a script that calls openssl right, it's fast to adapt for other domains, but the first time is hard.

I use https://github.com/lukas2511/letsencrypt.sh and it handles all the openssl stuff for you, I've found it to be really nice and light-weight. You just give it a directory to put the ACME challenge files in and a list of your domains

Why do you have to be a master? Just copy-paste the commands given in the README of the repo, replacing the domain for your own.

Well, at least on my computer, they were mostly broken.