Installed the lite version to try.
1. Doesn't save FB App ID
2. Social Gallery logo in the free version is a bit 'in your face'. I understand the need to encourage folks to upgrade but still.... make it a bit more subtle!
3. When I click on my social share buttons at the top of my pages, I get a quick view of this plugin appearing. Say I want to share my page to Twitter. I click on the Twitter share button but I get to see the a snippet of this plugin's lightbox appear... before it vanishes and with no share to Twitter. I click on the Twitter button a 2nd time, then it share to Twitter.
4. Clicking on my share Email button, doesn't work at all. I get an error saying "You must specify an "href" attribute to the iframe."
Deactivate this plugin and my social share buttons work perfectly and so it is this plugin which is causing problems.
EDIT: In view of the very positive reply from the plugin author, I have changed the rating to 5.