The following definition of floating calipers is not correct.
<<The floating calipers are bolted, but they can moved back and forth to follow imperfections in the rotor.
However floating calipers dont stop very fast, they are found on early model 300Es.>>
Floating caliper have the piston on one side only, pressing on the pad on the piston side and then drawing the moving portion of the caliper containing the other pad toward the disc. So, the caliper moves a bit when the brakes are applied. The main reason floating calipers are used is cost since they are a bit cheaper to manufacture. There is no particular disadvantage in them in everyday use but it's true, I think, that true high performance cars use fixed calipers with one or more pistons per side. Or, old and slow ones when things cost less. Disc imperfections don't come in to it.
My C280 used fixed on one end and floating on the other. My C320 uses floating on both ends. As does my Porsche. It's all about cost.