Testimonials sections are a great idea so your users can see feedback from existing users so they can get some peer feedback on products. Having positive testimonials on your website will urge new visitors to take action and possibly engage in a purchase decision or continue using the website/service.
Having votes of confidence from peers is a powerful selling tool as opposed to pure sales messages from the website itself. Testimonials just provide another dimension of sales/information for your users to take advantage of and to sell your product.
To see a full list of features for the testimonials modules please click here.