Pulsing Brakes on Normal stop

Lately my Yukon brakes have been pulsing at the end of a stop - the last 20 or 30 feet on a normal stop. I feel it in the pedal. The GM dealrer wants to replace both hub sensors - does that seem right, especially at $225 each plus labor? Thanks.

My 2001 GMC Yukon XL does the same thing. I've been told that I need brake rotors and that the vibrations comes from the warping. I need to know the answer as well.