I've been using this mouse for over 7 months now, and I really like it. It took me about half a day to get used to it, but now I don't want to go back to a regular mouse anytime soon.
Gravitational force is calculated by the (gravitational constant * mass of the 1st object * mass of the 2nd object) / (radius or distance between the two objects^2). Therefore, the more the distance is, less is the gravity. Besides, it is more natural for our wrists to be turned sideways rather than flat – think of what you do with your hands when you walk.
Most people with office jobs spend 7-8 hours a day in front of the computer, and I am no exception. And this is a significant part of your day. So if I could spend $6 on something that will help me keep my wrists relaxed 1/3 of my day, damn right I'm going to do it.
This mouse has 4 buttons and a jog wheel altogether. Two buttons, for the left and right click, the jog wheel only moves forward and back, it does not go sideways. The jog wheel is clickable, which is pretty convenient.
There are two more buttons on the side, which do not do anything, unless (I imagine) you assign a function to them manually, which I didn't bother doing. The click sound isn't too loud, and is within a reasonable level.
Also, I enjoy seeing the reaction of my coworkers when they try to use it for the first time. The IT guy really loves it, every time he needs to show me something he goes “Aha! This mouse again!”.
To sum up, very well worth the money in my opinion. Don't think twice, folks, this mouse rocks.
Product link: http://ali.ski/0Q5pT (AliExpress)