What are some alternatives?
When comparing Digicert and VeriSign, 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).
GlobalSign - GlobalSign offers a range of SSL Certificates with the strongest 2048 bit encryption and value add features to ensure your website is protected.
DNSimple - Domain Name Service with low cost hosted DNS, an easy to use web interface, and a REST API for automation. Hosting DNS has never been so simple.
GeoTrust - Guarantee online customer security with SSL certificates from GeoTrust. Purchase in bulk, manage multiple certificates & become your own Certificate Authority.
GoDaddy DNS - GoDaddy DNS helps manage website performance, reliability and security.
Comodo - Comodo, the leading Internet Security Provider offers Free Antivirus, SSL Certificate and other Internet Security related products with complete protection