I was in a hurry to buy. The old M-304 molecule is better in ergonomics than this one, and all the buttons are tighter and more pleasant, they have not been gouged for so many years of use, only the sensor is noticeably worse there and it is wired. Got pros: + excellent sensor, which is what it is. + weights, I do not use them, but let it be a plus. Some cons: - Probably this is my subjective opinion - an uncomfortable grip, the hand gets tired, it would be lower to make it. - Akum sits down pretty quickly (the backlight is all off), literally in a day of use, it charges for about an hour, what's the point in such "wireless" if once every couple of days you need to stick / poke a wire that is hard and hard to insert, although it can be plus - less likely that the nest will become loose. Somehow I got used to the fact that in old wireless rodents the battery lived for half a year. - the side buttons are "poorly pressed", and the main ones could work better, given the price. - software, the mouse is lost, the settings profile constantly crashes, so it's better to reconfigure the default one and not do others, it's normally configured only when connected by wire, in wireless mode every three times.