Testimonials Showcase for WordPress is the best well made and up to date Plugin built to display testimonials and reviews.
Testimonials Features

10 Predefined Responsive Themes
Grid Showcase
Slider Showcase (multiple features)
Filter Showcase
Submission Form
Product Review
Rich Snippets integrated
Fully Responsive&Retina Ready
Special Colors
Multi-Language
“Read more” option
Multi-Groups
Multiple Ordering
Characters custom limit option
Multiple Slider Pagination Themes
and many others features…