While all SSLs use the same technology and standard of encryption, the different certificate types have distinct requirements and characteristics.
Things that will factor into your decision include whether you have a personal or business website, the robustness of validation you desire, how many domains you need to protect and if your website uses subdomains.
Personal vs Business Website
If you are running a blog, simple brochure website, or internal facing domain for employees, a Standard Domain Validation (DV) SSL should give you the coverage you need. DV SSL certificates have the added bonus of being the fastest to issue and can be authorized in minutes.
If you're invested in your reputation and place a high value on being perceived as trustworthy, a high assurance Organizational Validation (OV) SSL certificate is worth investing in. OV SSLs validate that the domain belongs to a registered business and displays the validated company information in its site seal. OV certificates typically take a little longer to vet, approximately 1-3 business days.
If you are running an e-commerce website or simply want the prominent, universally recognized green bar that is synonymous with security and highly regarded global brands, you will need to select an extended validation (EV) SSL certificate. The validation process for EV is more comprehensive and takes approximately 1-5 business days to issue.
Multiple Domain Names
If you have more than one domain name, a multi-domain (MD) SSL certificate will save you money and time. Multi-Domain certificates are a convenient choice for businesses that own multiple domains or TLD extensions, eliminating the need to purchase, install and manage separate SSLs for each one. These certificates cover all manners of fully qualified domain names (FQDNs) including publicly accessible web addresses, private hostnames, IP addresses and more. Multi-domain SSL certificates are available in DV, OV and EV options and many can extend their protection to 250+ domains.
Website with Subdomains
If your primary domain has active subdomains - for example, mail.domain.com, shop.domain.com, members.domain.com, test.domain.com, dev.domain.com, etc. - a Wildcard SSL certificate can be used to protect them all, as well as future ones that you might create. Wildcard SSL certificates cover one domain name and an unlimited amount of sub-domains, and are available in DV and OV options.
Increasing Visitor Confidence
As indicated above, the vetting and validation process for DV, OV, and EV SSL certificates vary in intensity, with OV and EV requiring additional information and verifications such as confirmation of the business' ownership, and in the case of EV, that your business is registered with a government authority. Generally speaking, the more in-depth the validation, the more confidence and trust you establish with visitors. OV and EV certificates also include more prominent trust indicators that get displayed on your website.