S Hetjens

This plug-in restricts access to blog and feed. All anonymous visitors will be forwarded to the login page of WordPress 
before accessing the blog content. If access is restricted, rss and atom feeds will be disabled, too.
The feed can be activated as a private feed for each user. Every user will have a unique feed url to access it. That 
url is based on the username and an md5 hash of the hashed password stored in database. This plug-in will modify all 
by wordpress inserted feed urls to the user specific ones. But be carefull. If you content is confidential you should 
not activate the feed. There is no way to check which services are reading (and maybe publishing) the feed’s content.

Hetjens Registered Only

This plug-in restricts the access to blog and feed. Visitors need to login before accessing the blog. It offers a private feed for every user.

curlybracket

This plugin redirects non authenticated users to a page of your choice or, as per default, to the login page. 
Posts, categories, feeds, tags, taxonomies, author pages and search results are restricted to authenticated (connected) users. 
Only pages are public. So if you have a homepage defined, then this page will be accessible.

Very basic content restriction

Restricts access to all content except pages for non authenticated users.

Hetjens Registered Only vs Very basic content restriction