Achievement widget
When to use it
When the number is the story. A business with 4.8 from 600 reviews has a credential, and a feed of individual reviews undersells it.
It reads as an award mark rather than as a widget, which suits an about page or a header better than a product page where a visitor wants to read what people actually said.
What you can set
Show or hide the rating, review count and source icon
Size
Inline or floating
Click action: open the reviews popup or the source profile
Where it works best
Headers, about pages, the top of a long landing page, and anywhere a credential belongs. Less useful on a product page, where the visitor wants the detail.
Every layout takes the same sources — Google, Facebook and 68 others — so the choice here is presentation, not capability.
The other layouts
There are fourteen in the editor and they compete with each other for the same visitor, so it is worth knowing when a different one is the better answer. The full gallery shows each one running.