Yet, multiple of these devices have been released in the last 20 years. The concept itself is old and over-used. We precisely know the success rates, and frankly their own tests aren't exactly reliable. What they are making probably works in theory, but less so in practice as it still requires a large amount of work to become lucid even with this device.
There is nothing wrong with being skeptical in a controversial product such as this one, especially considering the price. Until they can back up their claims with multiple outside independent statements, we should remain weary.