4 stars because everyone's tastes are different. In terms of quality and construction, it is very good.
If you want a hard surface for fast movements, then this is for you. It was purchased 5 years ago when it still cost 70+ euros because it was theoretically new as a hard mousepad with LED, so now the purchase price is quite good for anyone who wants to try this surface without crying over their money in case it doesn't suit them.
The only downside is that the mouse feet wear out quite quickly due to the surface, and that is understandable. Personally, I thought it suited me until I recently bought the "Corsair MM700 Extended Gaming Mouse Pad XXL," which was released a few years later.
Many also place the MM700 on top of the MM800, but I found it to be too much.

+For LED customization, you download the Corsair program (iCue) through their website and change their function from there.

The mouse glides very fast. Quality construction! Nice lighting and beautiful design.

Good little gadget, but not worth 80€. At 45€ during sales, it's worth considering.
The USB port for a mouse or anything else is a plus, as well as the program that allows you to adjust the LED speed. But most importantly, the mouse has a very nice feel to it. Well done to the company

Owner of 4 months as the kids say, very good build quality, the mouse goes smoothly on it, overall it is a gem on the desk. Until 1 month ago, I had no problems until they started...

The mousepad has been here for 1 month, when the computer shuts down, the mousepad still receives power, that's why the 2 stars.

1) For some reason, I can't change the color, it always stays RGB no matter what I do, I can't even turn it off or put it on blue or red.

(Yes, I uninstalled the program and downloaded it again)
(Yes, I unplugged the USB and plugged it back in) - (at first it works after 3 minutes it goes back to its own)
(I also updated the program, same thing happens)

That's why the 2 stars, I paid 45 euros for it, unrelated.