As with everything in aviation, there are tradeoffs. Neither one is better or worse than the other, and they both fly pretty much the same. The Cherokee is a little lighter than the 172 in pitch, thats really about it when it comes to flying her.
Now, other minor differances- the Skyhawk will give up about 5-7 knots to a comperable Cherokee in cruise, (no fair comparing a 172L to a Dakota 235, or even a Cherokee 180) but make up for it on the low end with about a 5-7 knot lower stall speed, and shorter takeoff and landing distances. Gross weights will be roughly the same, differances being the year; older 'hawks had a gross of 2300, when the flaps were restricted to 30 degrees the weight was increased to 2400, and another 50 lbs was added for the new R models. The only hard weights I have are for the -28 series are a Warrior 151 at 2325 and an Archer III (181) at 2500.
The flaps on a Cessna are like giant barn doors, especially older ones with 40 degrees of flap travel. Cherokees, OTOH, are much smaller. Inside, there is a little more elbow room in a Skyhawk than in the Cherokee, and the back seat is cavernous in the Skyhawk compared to a Cherokee. Entrance and exit are also easier in the Cessna, with two large doors on either side. Given that, however, passengers seem more comfortable in the low-winged airplane for some reason.
The Cherokee's also generally have longer range, due to having about 8 gallons more usable fuel, depending on the year.
In all, I liken the PA28-140/151/161 series to a small sedan, comfortable and gets the job done. The 172 is more like the SUV- it's slow, roomy, and in a pinch can get in and out of spots the Cherokee can't. The PA28-181, however is the luxury sedan. Goes fast and can carry a decent load.
Hope this helps,
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