for extra pwnz [MLG] > https://www.youtube.com/watch?v=r2wyWPBRfxY

On a serious note, zoot used a sensei and he said it lasted like a week before breaking iirc. Perhaps he was unlucky, but it is a factor to be considered if you go with the sensei.

SS Sensei MLG's Avago 9800 sensor is 9500's evolution (g9x, xai, g500).
it's stated here that 9800 is not accurate as well as its antecessor.

This architecture does not or hasn't provided 1:1 linear tracking within it's rated specification window of 150 IPS. [...] the accel curve is within 5% of its linear range. [...] With lower IPS movement, the Xai hits a small negative acceleration curve around 0.6 or 0.7 meters/s or 25 IPS. After 1meter/s or 40 IPS, the sensor goes into a wobble effect of positive acceleration above the linear range. This remains the case with newer 9800 branded mice as well. Last update 7/28/2012
The 9800 branded variant by default has a smoothing curve to clean up cursor movement at higher CPI.

All I can say since I don't own one.