It's not the prettiest mouse but for FPS games the sensor is beast and it doesn't fail you exept if you get one with some errors, tho it rarely has any problems.
Also if you using razer mousepad u should change that too with zowie cuz it doesn't feel that good with razer mousepad cuz material
ec1-a uses a 3310 sensor compared to 3360 of sensei 310 (which is better). the build quality of steelseries and zowie is both shit, probably the only thing better is the mousewheel@zowie (and yes i use zowie as well).
sadly zowie seems to be the only brand still using the worst sensor in the top mice market (3310) when mostly all brands are using some variation of the 3360 (3366 3388)