What are some alternatives?
When comparing CAcert and COMODO SSL, you can also consider the following products
Digicert - Encryption & Authentication
Let's Encrypt - Let’s Encrypt is a free, automated, and open certificate authority brought to you by the Internet Security Research Group (ISRG).
VeriSign - VeriSign Authentication Services provides solutions that allow companies & consumers to engage...
SSL For Free - Free SSL Certificate issued in less than a minute.
SSL2BUY - SSL2BUY is the foremost SSL certificate provider of online security solutions for businesses.
Cheap SSL Shop - Cheap SSL Shop is the cheapest SSL certificate provider.