When you want to get testimonials to use in your marketing you will need to realize that the customer will not give this easily or for nothing. The very nature of a testimonial is to let a company know (and they use it to let their potential customers know) if a product performs like it should or as was advertised. You may want these kind of testimonials but the really valuable ones are the ones where customers are thrilled, even overly thrilled. Learning how to get client testimonials is easy, just give them a reason to want to give back. They know you use these in advertizing and if they are truly thrilled with your product they will leave them, their payoff is in your overdelivering on their hard earned money.