I have lenovo M6811 Laser mouse.
Bought for 600
Its good and has interchangable dpi settings
two extra buttons near thumb which can be configured.
Nice design
It suits me well. It well fits for 600rs.
The only thing i dont like is its plastic finish - looks like a china made (afterall - lenovo is in china

)
wow, i have the same one.
the only problem is, when you happen to pres both the mouse buttons at the same time (M1 and M2), the dps button gets activated, dunno why or how.
and the scroll wheel is a bit iffy, else, i use it for tf2 and other fps/rts games, and im totally satisfied with it.
also, its got a nice moulded thumb rest, which has a rubberised inset. very comfy

before, on my old mouse, i used to get finger/hand/wrist problems. none with this mouse.