Oh yeah, and also who the heck designed Sigma's magnets?

Everyone else uses screw-on type magnets.

The genius at Sigma decided to use a design that either seizes on bladed spokes as used in Mavic wheels and other popular spokes like Sapim CX-Ray and makes it very difficult to take off, or doesn't fit on thin, round ones, like DT Revolutions, which makes the magnet move around.