What are some alternatives?
When comparing ClickSSL and Digicert, you can also consider the following products
Let's Encrypt - Let’s Encrypt is a free, automated, and open certificate authority brought to you by the Internet Security Research Group (ISRG).
SSL2BUY - SSL2BUY is the foremost SSL certificate provider of online security solutions for businesses.
VeriSign - VeriSign Authentication Services provides solutions that allow companies & consumers to engage...
SafeCyberSSL - SafeCyberSSL is a platinum partner of leading Certificate Authorities.
Comodo - Comodo, the leading Internet Security Provider offers Free Antivirus, SSL Certificate and other Internet Security related products with complete protection
ComodoSSLstore - ComodoSSLStore is one of the largest global SSL certificate providers.