  Cooling the centre-of-mass motion is an important tool for levitated
optomechanical systems, but it is often not clear which method can practically
reach lower temperatures for a particular experiment. We directly compare the
parametric and velocity feedback damping methods, which are used extensively
for cooling the motion of single trapped particles in a range of traps. By
performing experiments on the same particle, and with the same detection
system, we demonstrate that velocity damping cools the oscillator to lower
temperatures and is more resilient to imperfect experimental conditions. We
show that these results are consistent with analytical limits as well as
numerical simulations that include experimental noise.
