Hello,
I am going to tell you why Let's Encrypt SSL is sucks and why you should not use this until you have a lot of free time and don't have a issue in restarting your Web Server on every few month.
Demo Domain: Lets Encrypt SSL is installed on PreMadeKB.com (Note SSL will expire on May 2016)
I was so excited to offer Let's Encrypt Free SSL to our customers but after running manny commands and when I get success in generating my First SSL, I was so happy but now I can issue a Free SSL to my customers and even can use on my blog.
Look at this screenshot, Its look so awesome..
But I disappointed when I find that expiry date is after 90 days, mens only 3 month is life of Let's Encrypt.
Do you want to renew your SSL on every 90 days?
I am sure you don't want to waste your time and don't want to restart your webserver on every 90 days to save only few bucks on SSL, Its a better to purchase a paid SSL instead of Let's Encrypt SSL. Well some of peoples who manage lots of domain want to use it even If it will take few hours to issue a SSL and install it. Maybe theire is some of automatic softwares are available which can install/renew SSL for you automatically but cost of those software is high.
Even Let's Encryt did not use their own SSL on their Domain.
Note: Their SSL is still in beta mode so maybe later they will extend expiry period.