yuri

IMHO, this is as good as giving me http://www.google.com. Please kindly point me to the exact page that lists the chains.

Well, to me the most important thing is the encryption and hence I won't say which is better since they are both the same in terms of encryption strength. However, there will be two groups of people - one say you should only use single-root while the other say all the way for chained-root. IMHO the pros and cons are arguable, and you can find all sort of reasons from google, e.g. http://www.trustico.com/chained/chained-ssl.php vs http://www.whichssl.com/intermediate_certificates2.html One note though, you do need to install the root cert for chained-root SSL. I do prefer single-root SSL, but that's purely my personal preference.

RapidSSL is "issued" directly by "Equifax Secure CA" (https://knowledge.rapidssl.com/support/ssl-certificate-support/index?page=content&id=SO8834&actp=LIST&viewlocale=en_US) PositiveSSL is chained from "AddTrust External CA Root" - "UTN USERFirst Hardware" -"PositiveSSL CA". I can't seem to locate this information from the Comodo knowledge, but I did lookup the details from my PositveSSL cert.