Does review schema work for local businesses or just products?

[Kristen]

I'm wondering if anyone has had success getting the review stars using schema to show in organic search results.

I have everything implemented on a clients' site using the WP customer reviews plugin.

The structured review data displays correctly using Google's testing tool, but when I do various searches for the testimonial page in Google, I see the author photo, but no stars.

Anyone successfully implement review stars for a local business?