On version 4.1.1 (straight out of the box and with no themes or other plugins added) I installed this and find it doesn't do anything.
There is no control on the Page Editing screen to turn comments on/off and when a new page is posted the comments box is available for anyone to post comments.
I can only presume that the five star reviews are from those who've used this plugin on an older version of WP (or I'm being a right idiot and missing something obvious).
Was still able to add a million comments to both posts and pages.
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