You still playing? Thought you gave it up for Lent or something
Mice are like DSLR's or something like that...the biggest part of using one successfully is the user. I can't honestly say the new mouse makes me better...
but it does feel a heck of a lot nicer in my hand so I can play longer.
Actually there is lot more to mice, a mouse needs to suite its user, so,
a. Shape
b. Buttons
c. Sensor
d. Weight
the order is in relevance to the game type. Shape is the most important as size will dictate your hand grip, a) Palm, B) Claw or C) Fingertip. I will suggest that many look at Zy's reviews as he touch base with FPS suited mice.
Then you have to look at design, mice which are restricted by their cable need a bungee. I have a Razer bungee, the dumbest tool, but best mouse assistant ever made.
Lastly, tracking, a sensor is only as good as the area it is tracking on. No pad is made the same, and no mice tracks the same in design so you will need to acquire a pad best suited to your mouse. That Arena pad that I have linked to, bargain, Zy has a review on it,
http://www.rocketjumpninja.com/cougar-arena-review/
All which are small things, but small things add up, and only people serious about gaming should consider expensive equipment, because well the equipment is only as good as its user.
Buying a Zowie mouse will not make you a pro player. Besides, most gamers with G403 mice is average at best
As Prod said, the part that I put in bold, that is what every casual gamer should look into, make your hand happy.