It basically boils down to one issue - cost! Most early disk brake systems were fixed caliper but as disk brakes propagated through all price levels, the floating caliper type became more popular because it has fewer precision parts, which makes it cheaper to build.

The primary disadvantage is greater flex, which can affect pedal feel and lead to taper wear on the pads, but these are not issues with most cars used for normal street and highway driving, but almost all racing designs are fixed caliper.

An interesting new design is the new Corvette Z06. Both ends have fixed calipers (floating on the other models). The front calipers have six pistons, four at the rear, and each piston has a separate pad - a total of 20 pads on each car.

The separate pads should virtually eliminate pad taper in heavy duty service such as racetrack hot lapping.

Duke