Certificates SSL with domain validation are fastest in emitting themselves, only need to verify the domain (by means of a mail sent to your e-mail) to complete the process. This way you will obtain an economic certificate and in a very short time.
Certificates SSL of validation by company need additional information to finish their emission, is necessary to validate the domain by means of an e-mail, to send documentation of the company and to respond to a telephone call that will realise the emitting company of contracted certificate SSL.
Comodo InstantSSL Pro
Certificates SSL of Extended Validation provide the greater degree of confidence to your visitors since they will show the bar of directions in green while they sail by your website. This certificate type needs, in addition to the verification of data of the domain and the company, of the shipment of signed forms to be able to obtain it.
Comodo EV SSL
Certificates SSL Wildcard will allow to add security you SSL to all the subdomains of your domain by means of an only certificate SSL, this way, if you have different subdomains will be able to make use of the same certificate without additional cost.