I'm not doing my own as the general public will be logging into some sites and I don't want them to have to worry about certifcate pop-ups.

I'm looking to have about 10 domains to start using them.

This is on a Rackspace cloud server so I would prefer to do them all of of one IP as there's only a max of 4 per server.

Is there any major differences between the following?

Right now GoDaddy seems the best as I don't need anything special and they have good prices 10 domains for $170/yr http://www.godaddy.com/ssl/ssl-certificates.aspx?isc=sslqgca02a&ci=9039

StartSSL looks like it has multiple domain names for $49 and I'd imagine $49 for each additional domain? They look to be for 2 years though: https://www.startssl.com/?app=39

Comodo seems ok, but you only get 3 domains for $330 and then each additional one costs $95! http://www.comodo.com/business-security/digital-certificates/multi-domain-ssl.php

Geocerts have 10 for $549, but they're aimed at business: http://www.geocerts.com/ssl/tbidmd

GlobeSSL has one for $155 but again, that's 3 domains. Though it's only $50 USD for an additional year. https://www.globessl.com/SSL-Certificates,Globe-Multi-Domain-SSL.htm#