I just spent over 20 minutes trying to find the shortcode for a sidebar widget when you could have put it in the installation or description section. I had to look in the code for shortcode names - annoying.
In other news, it works though requires a lot of css formatting to look decent on most sites. It's practically unnoticeable to readers and manual "attention grabbing" styling is needed of people will never know it's there.
A widget to display latest or random reviews would be awesome instead of having to use short code, one that dynamically rotates even better.
Otherwise, good job.