I've been using testimonial-rotator on a client's site in combination with wp-customer-reviews.
wp-customer-reviews has not sidebar widget and no randomizer
Does testimonial-rotator support hReviews and Rich Snippets?
Google and other search engines have agreed to rich snippets and hReview to index reviews on websites.
In which case, not only would your plugin display testimonials/reviews; but, the search engines will also index them as testimonials/reviews ...