Suppose I want to buy SSL certs for a domain, say
xyzzy.com and three sub-domains (www.xyzzy.com, smtp. and mail. for example). There seem to be several options: multiple single-server certs, a "multi-domain" cert or a "wildcard" cert. This question has to do with technical reasons for choosing one type of cert over another.
Currently the reseller I'm considering (NameCheap->Comodo PositiveSSL) prices certificates as follows (annual cost):
Single server 9.00 Multi-domain 29.00 Wildcard 94.00
So for a total of 4 names it would seem a multi-domain cert would be the minimum cost, and for fewer than 4 I should just buy single-server certs.
Note that this is not for e-commerce or personal information, so extensive verification is not needed.
Is there any technical reason for choosing something other than the lowest cost alternative?