From strict requirements point of view, it doesn't matter as long as the CA supports issuing the different certificate types required as detailed at https://technet.microsoft.com/en-us/library/bb680733.aspx (for 2007) or https://technet.microsoft.com/en-us/library/gg699362.aspx
(for 2012).
In either case however, it will be a very large logistic challenge however to deploy the needed certificates to client systems and to renew them when they need renewal.
There is also another difference you need to worry about with Microsoft CAs and that's whether it was installed on Windows Enterprise edition or not (at least for Server 2008 R2 and before). Only these CAs can issue certs based on custom templates which
are required for a Site Server Signing certificate in 2007. If the CA is running on 2012 or later or you are running ConfigMgr 2012, then you don't have to worry about this later implication, but the former is still a huge challenge not easily overcome.