Hosting configuration for Prosites

What is the recommended configuration for a company selling Pro sites to users?

Should the domain.com of the sales site be one of the network sites in the WP multi-site install ?

Are there pros and cons of having it in or out of the network? I am favoring out, just intuitively, but can’t say why, and thinking to put the multisite on members.domain.com or similar. I guess I am thinking that way, my main site stays as simple as possible, and doesn’t need ProSites.

OTOH, if domain.com were “in”, then it would get any new plugins automatically, but I wouldn’t want any resource or plugin limits to apply….