"This Plugin allows you to select specific users by user name, or by role name who can view a specific post content or page content.
Basically it adds a meta box to the post or page edit screen and lets the user select specific users by name or roles and then when you call that page content using “the_content();” function it check using “the_content” filter if the current user is one of the users you have selected or if his role match’s the roles you have selected and shows the content, otherwise it displays a message"
This is the official description.
When we selected specific user or role, the plugin added meta value in wp_postmeta table to control the content display. The result on front-end looks weird. It shows the title as usual, but no content.
Conclusion: for security, this plugin is good to protect the content. For user experience, this is not acceptable.