Unfortunately, no, there are currently no hands-on impression videos of the Stadia controller. However, there is a video available on YouTube that provides an overview of the features of the controller. You can view the video here: https://www.youtube.com/watch?v=tlFrs6BrpBo.
Stadia has also published a blog post on their website that goes into more detail on the functions and features of the controller: https://blog.google/products/stadia/take-play-anywhere-introducing-stadia-controller.
The Stadia controller has an array of features that make it much more than a conventional gamepad, such as a dedicated Google Assistant button and an adaptive trigger buttion that lets gamers adjust the tension of the trigger along a continuum. It's also equipped with four buttons that can be switched between a control pad, ABXY buttons, or custom functions. Additionally, if you're playing on a mobile device, the Stadia controller can be paired with your device via Bluetooth connection.
Overall, the Stadia controller provides a unique and comprehensive gaming experience, allowing players to take their games to the next level and truly play anytime, anywhere.