After flying 300 hrs in a 172 and then selling it to buy a PA28 that I have flown 60 hrs in heres my pound of flesh...........
172 great for: Short strips, cheap maintenance, robust, roomy and gains value quicker than PA28.
172 bad for: Draggy design, not as attractive as low wings.
PA28 great for: General cruise comfort (wider but sadly shorter inside), looks great, faster.
PA28 bad for: Fiddly oleos, more AD's, rear passenger leg room.
My vote..........if it's a bomb proof lugger you want go for the 172, if it's a comfy cruiser you want go for the PA28.