Hi Don, I have been working with Domain Access a year now. For your needs it will work very well, the primary problem is that another modules are not build with multiples domain in mind. One example is the contact module, you will have a unique contact shared in all your site, I`m modifing the contact core module to support Domain Access, but it wasn't approved yet as a new project. The module is very easy to use, no hard-code configurations are necessary, all the job are point a new domain to your drupal instalation and configure the Domain Access to receive the request coming for this domain and the magic happens. .
Att,
Pablo Lacerda de Miranda Software Engineerer Ci&T - Campinas pablolmiranda@gmail.com +55 11 8701-1086