One thing to keep in mind is price.
Here in Canada, a good PA28-140 can be had for a good $20k less than a C172 with the more desirable Lycoming O320. The -140 has a few inconveniences though, like lack of a baggage door. It is said that a -140 has less useful load but that will depend on the equipment on the bird; and standard tanks on the 172 are 38 gal, whereas the PA28 can hold 50 gallons and has convenient tabs to mark off, I think if memory serves, something like 36 gal.
In fact a good late-model PA28-140 and an older 172 (with the 6-cyl continental) go for about the same price. The Lycoming 172s are priced beyond all good reason.
In short though each type has its merits and drawbacks. I happen to prefer low-wing...and brunettes....! For some it's high-wing and blondes!