What are some alternatives?
When comparing Digicert and COMODO SSL, 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).
VeriSign - VeriSign Authentication Services provides solutions that allow companies & consumers to engage...
CAcert - CAcert.org is a community-driven Certificate Authority that issues certificates to the public at...
GlobalSign - GlobalSign offers a range of SSL Certificates with the strongest 2048 bit encryption and value add features to ensure your website is protected.
GeoTrust - Guarantee online customer security with SSL certificates from GeoTrust. Purchase in bulk, manage multiple certificates & become your own Certificate Authority.
SSL2BUY - SSL2BUY is the foremost SSL certificate provider of online security solutions for businesses.