After about 4 months, the rubber grip on the left hand side has come off. This was just two smooth surfaces glued together and is a very poor design.
You have to run awful synapse crapware to stop the mouse from constantly changing colours, the most annoying setting possible. They could have easily picked a more sensible default setting, or allowed you to choose a colour setting without having the software running ALL THE TIME but they want their cancer on your computer all the time so they hobble the device. The software requires an account to run, and regularly nags you to update it, a process that is largely manual forcing you to constatly interact with this dreadful software you don't want in the first place.
The mouse is way too light, requiring me to blue tack $2 coins in strategic places to weigh it down a bit.
The side buttons are almost unusable because it tries to put 2 buttons where neither is comfortable, instead of one button that would be usable.
The plastic surrounding the sensor underneath is very sharp around the edges and is a perfect scoup for dust and paper particles which it traps near the sensor, causing your game to wildly swing around 180 degrees.
Overall, a horrible experience. I don't know why this company is as popular as they are, their product and software are garbage.