Basic SSL is a quick, simple and useful certificate. However, paid SSL certificates include many more advantages so that your clients will trust you that much more.
They include economic coverage that gives you compensation if there is an error in the certificate.
They have a “Dynamic Site Seal” which is a seal you can put on your website to show the validity date. This means that your clients can trust that your website is permanently secure.
They are valid for domains which include words from registered trademarks.
They validate the organisation (in the case of Thawte Web Server SSL certificates and Web Server Wildcard SSL certs.) and they have extended validation (True BusinessID EV SSL certs.).
They are available for more than one sub-domain (in the case of Thawte 123 Wildcard SSL certs. and Thawte Web Server Wildcard SSL certs.).