PA28-151's MZFW could carry 30 or 40kg more than the 172
from distant memory, but the 172 had longer legs fuel wise
for a similar payload. Admittedly I'm a bit out of practice by
30 years.
Short trips with fat slobs + full baggage - PA28, longer trips
with same slobs but reduced baggage - 172. Slightly off the
topic but best of the lot was the C206 - full tanks, full bums
and 6 slabs in the back equalled MTOW. The CofG check was
simply to push the tail down...if it came up again you were in
the envelope.