The SSL and TLS protocols are almost identical: Both encrypt data, but additional improvements in newer protocols mean better online security.
The common practice combining public and non-public domains could prove problematic as new extensions are made open for public registration.
Which SSL certificate to choose is more than just features and browser compatibility. The SSL customer experience, tells a different story on which SSL you should pick.
NGINX, the fastest growing Web server among high traffic sites, uses OCSP-Stapling to enhance trust in verifying SSL Certificate validity.