@aquamatrix
MX 518 is a LASER mouse, but uses Laser Engine 1 technology with 1600 dpi, whereas G5 has LASER Engine 2 tech with 2000dpi.
Its better to stretch 1k more to get the G5 itself. Its got lot more features,perfomance and comfort.
G5's feet are best and it has weight adjustment and its software support is superb[ but only work well in Xp, nut even in 2000].
Im currently using the iball one and its really gud for the price. Good controll of the crosshair and comfortable on hands too.Go for it if u are low on budget.