At my first SteelSeries Sensei RAW I had a few (2-3) months a malfunction that the mouse wheel sporadically jumped up when down scrolling. Let alone the use of FPS in which the mouse wheel particularly comes into play (not in my case), reading texts for me - it was news, facebook, PDF articles, forums - one frustration because you when scrolling and additional jumping literally loses the thread in the text - "in which line I was again?". For a mouse this price a no-go.
I could have sent the mouse to SteelSeries - somewhere in Holland, and the whole Schose would take 2-3 weeks to complete, in which I would have no mouse should hope I get it back. So I bought good will again (!) SteelSeries Sensei RAW mouse to send the old one if necessary SteelSeries warranty and / or to use as a substitute.
You hardly believe it - after just two months jumped the mouse wheel upwards again. The same defect in a totally different mouse (meanwhile also other PC).
I will both mice to guarantee to SteelSeries send (postage paid one as far as I know myself), then check and if necessary (!) To make a repair, God willing.
I for one will again change to Razer and sell the two mice for a few euros. For the same price you get in the competition higher quality mice (also thumb buttons, DPI, etc.).
Never again SteelSeries!