Soliciting Testimonials vs. Review Copies...They Are NOT The Same Thing
Offering a "review copy" is a much better way to not only get truly valuable testimonials, but also constructive criticism that may save you from launching a product that is not market ready.
Just ask people for an honest review. Then ask them for permission to use their comments in a testimonial after they've given you their review.
If you merely ask for testimonials (even if what you mean to ask for is honest feedback), you're likely going to attract people that will sell their opinions for a freebie.
So you gotta ask yourself which is better for your business in the long term...
1) Listening to those who will tell you what you want to hear just to get a free copy of your product
OR
2) Listening to those who may not tell you exactly what you want to hear, but will be honest with you regardless of your emotional investment in your product.
Trust me...option #1 isn't going to fool your customers if the product isn't up to par. While option #2 could very well save you from putting out sub par offers.