I know it has been discussed but they were a bit old. I need follow up with most current information out there and from WPMUDEV Staff too.
I checked for multi site manager and not sure if its updated to work well. There is another site from http://bui4ever.com/web-itecture/wordpress_mu_with_domain_mapping to do it differently. I believe that multi site manager will do the job with less steps. Will it always be manual process to do the setup not automated when anyone sign up for the service to use their own domain toward to subdomain wordpress sites?