We migrated to Pressero from another platform about a year ago and have liked it far above our old platform. With that being said, one thing that was really nice was the ability to have one account as an admin and be able to log in to any site without creating an additional login for each site. I would love for Admin user accounts to have this feature for easier and quicker use across the board.
Davin, what we have is a User Impersonation feature. It is enabled in your account under Settings > General. With that enabled, you see a small blue arrow to the left of the site user on User Management > SIte Users. This allows for impersonating any user on a site.