The choice of which mouse is rather subjective. However, there are some important guidelines that you can follow that allows making a more accurate selection of which mouse you are going to buy. It is important to consider:
Sensor: it is essential to establish the quality of the mouse. Nowadays, there are two kinds of sensors: optical and laser. The first use of a LED light to illuminate the surface to be acquired as an image, the latter use a diode laser to track the movements, achieving higher resolutions of the captured image compared to a normal LED.
Hand Grip: there are 3 types of hand grips. The palm grip, which is the most common way that the palm of the hand and fingers extended, rest entirely on the surface of the mouse. The claw grip, where the fingers are kept as an arc and only the fingertips resting on the mouse. And finally, the fingertip grip, much like the claw grip with the difference that the palm of the hand rests on the pad instead of on the mouse.
CPI (or DPI): these are the samplings per inch of surface (erroneously many use DPI that instead refers to a term used in the printing on paper) that the sensor is able to acquire. However, it is important to emphasize that a higher value of this feature does not imply a better mouse. Indeed, it is often the opposite. Some manufacturers use software to create artificially sampling interpolated between two real, thus increasing the number of CPI at the expense of the accuracy of sampling. We stress the fact that a high number of samplings are exploited only at high resolutions and by the players that use a very high sensitivity in game. To make a very rough calculation of the CPI that we really need, you can do this: multiply by 4 the horizontal resolution used in the game by dividing by the number of inches required to perform a 360° circle with the mouse in an FPS game. For example, using the classical HD resolution (1920 × 1080) and doing a 360° 20 cm (approximately 8 inches) the approximate calculation will be: 1920 × 4/8 = 1000 CPI (DPI). So in this case the maximum number of samples per inch we're going to take advantage of it will be about 1000 CPI (DPI).
Lift-off distance: this is the height to which the sensor of the mouse will continue to process the images acquired after being lifted from the surface. Low values allow repositioning of the mouse on the surface with minimal deviations of the cursor due to sampling side while lifting.
Polling rate: this is the number of times per second in which the mouse communicates with the computer regarding movement. The standard USB port is 125Hz (or 125 communications per second). This standard is inappropriate in the gaming environment, where responsiveness is a key element. For this reason we always recommended you to set (even with the mouse driver if it allows it) a minimum polling rate of 500Hz (2ms latency) o 1000Hz (1ms latency). Both offers undeniable benefits compared to default 125Hz with 8ms latency.
In case you were wondering about wireless mice. Our advice is the following: if you're looking for a gaming mouse, wireless mice should be absolutely avoided. Their performances are not at all comparable, even to a mediocre wired mouse.