I've flown both and as already said each have their own good points and bad points....I actually like both types for different reasons.
I would base my decision on what variants are available at your airfield. A PA28 140 is not really a proper 4 seat tourer....with 4 adults on board you'll need to severely limit fuel to stay under MTOW. The same is true for earlier C172 variants.
I'd have a look at the POH for each of the aircraft at your airfield and convert to the one that carries the greatest payload.