The problem lies with using the mouse without the receiver i.e. Bluetooth only

:'(-edit-seems like the first problem at first was the firmware update

has rattle problem and jitters, second wouldn't even charge.

The first major problem is that both the 602 and 603 lack a tilt-capable scroll wheel.

Has a weird problem where I scroll down or up and it randomly reverses scroll direction.

Well, therein lies the problem

Never have any problems with lag, no issues with connectivity and even though I'm a left handed user it still works great for me.

I have updated the firmware that supposedly would fix this problem and problem has only gotten worse.

Well, therein lies the problem

My only problem, which is huge for me, is that the side buttons squeak

On top of that I also experienced the dreaded scrolling problem that isn’t fixed with drivers or software, it ruined games for me

But now I'm getting the dreaded scroll wheel problem

I think this mouse has a critical durability problem in the left switch

How this issue with the scroll wheel is still a problem in this day and age is just a sign of cheapness.