I had to update the firmware to the latest version before it was usable with my phones.
After that was accomplished, I got very good communication with almost no lag or difficulties to connect.
This means your mileage may vary depending on your phone/PC and you must be willing to perform updates and investigate a bit.
To be fair, I believe it is one of the best available. Wireless Display is a difficult thing to get right.
Came with no instructions. Power cord was substituted for a very short one, needed to change for a longer one, took forever to be delivered to my home.