6 Months ago I had to replace my Sensei because after 5 years the switches were just too broken. I mostly played League of Legends at that time and I decided to go with an Zowie Ec1-A. After 4 months ago I decided to switch to csgo again and I didn't encounter any problems with the Ec1-A.
But recently I tried the Sensei again and it felt so much better playing a fps with it than with the Ec1-A (shape wise). So I ordered an Zowie Fk1 to see how it fits me. And the mouse is pretty great.
I like the buttons, the build quality and the sensor. Just the mouse wheel is pretty bad because it can get stuck between two states and when you do a flick the mouse will will register a scroll.
But overall I like the Fk1, it just is not as wide as the Sensei and the Sensei still feels much better in my hand. The sensor of the Fk1/Ec1-A can register speeds up to 5.6m/s and I often reach around 4.2m/s myself. But the Sensei only goes as fast as ~1.7m/s currently which is pretty horrible.
I play csgo with 800dpi and 0.8 sens with 6/10 on windows.
Now I have also looked at the Rival 100 because it is similar to the Sensei but the sensor only seems to operate well at 500dpi. Now this might not be the biggest problem, but I am wondering if there are other alternatives?