Often depends on what you are after. For current mode
control in a switcher, high side or inductor current sense
offers pulse-by-pulse, during-on-time control and pulse
termination (useful for things like short circuit protection).
Low side sensing only works after the pulse has turned
back off and would not show realistic short circuit current
(as that might saturate the inductor and return less than
all the IOUT, to the low side switch).
But high side schemes tend to be slow, noise exposed,
etc. and high side sensing may work out better for ICs
than for piece-parts assemblies.
A high side sense that is fed a reference current and
returns a switching event (comparator) may be better
than trying to make a continuous-time sense amp (or
Hall, via its excitation and amp chain) go fast enough
to respond right, intra-pulse.