All three look well used but the KHS is the best value. Frame tubing is the same on all three bicycles. The components on the KHS are one generation newer than on the red Centurion and one level higher than on the pink Centurion. Plus, the clipless pedal and aero front wheel with low spoke count would be a big bonus for triathlons, even if they aren't OEM. Add in the price difference and it's a no brainer, provided it fits and there are no major issues. The savings will buy you the cycling shoes to go with hte pedals or allow you to put any work into the bicycle. The only puzzling thing about the KHS is that 600 Ultgra was a 7 speed group and this one is only 6 speed.