I've mostly got a good impression of the User Access Manager. I have my blog set up so a test user doesn't see posts or post titles to which the user isn't granted permission. This works in most areas including categories and post RSS feeds.
However, I'm having trouble with the comment RSS feeds. The user is still able to see complete comments in the RSS feed, including comments on posts that the user should not be able to access. Strangely, though, the post RSS feed functions properly.