You lose the cursor on the screen, sometimes you want to press somewhere else and it takes you elsewhere. It's fine for urgent situations.

I didn't go crazy to tell you the truth, but anyway it does its job.
It is definitely better than the previous one I had, which needed a new battery every 15 days.
This one lasts for three months

I bought it in October 2018 for €5.90 for use on a laptop and it was exactly what I was looking for. User-friendly, lightweight, and convenient with 6 particularly useful buttons for me. It does not activate if the receiver is not connected to the computer, so it will not consume battery if left on and a button is pressed while it is in a bag. It has a power-off button but also automatically goes into standby mode when not in use for a while and can be activated again by pressing a button.
In recent days (April 2020), it has been showing a problem with the left click (sometimes it double-clicks with one press or after holding the button down, for example, to highlight something, it functions as if I am clicking again when I release it, canceling the highlighting). I tried to improve it through the settings but for some reason, it refuses. However, it doesn't bother me at all. I consider that it has more than made up for its cost. It is clearly a value for money choice.