[lukas2511]

Well, there are two major reasons why I think letsencrypt is great right now.

One thing is that it just works, it's a trusted CA and there is no bullshit "please install this cert" stuff.

The other thing is the automatisation. There were some CAs with free certificates before, but you had to manually click around in a webinterface, manually put a file on a webserver or copy an ID from an email, or whatever to verify that you are the owner of the domain. This process often took from around 30 minutes to several hours, while the acme-protocol is designed to handle validation in seconds, and it actually works. You can start a new project, send of the signing command, and in seconds you'll have a certificate.