ivan-ovsyannikov

The plugin automatically adds keywords in heading from tags. Uses for this purpose one SQL-query as <code>get_the_tags()</code> works only in Loop. The ‘Quick META Keywords’ plug-in uses categories for keywords, this plug-in uses tags. The ‘Tags2MetaKeywords’ plug-in does not add automatically.

Tags2Keywords

The plugin automatically adds keywords in heading from tags.

Steve

This plugin uses custom fields to allow the page title tag to be customised and differ from the actual page title.
Both meta descriptions and keywords can also be added if required.
Page meta details can be modified on any publicly accessible post type, such as posts and pages, as well as custom post types.
Theme and plugin developers should note that it is possible override the page title within your templates by setting <code>$wppm_title = 'Newly defined title';</code> before the call to <code>get_header();</code>.

Page Meta

Adds the ability to override the page meta title and add in meta descriptions and keywords for pages.

Tags2Keywords vs Page Meta