Neither aircraft is hard to land, if you find they are then you're doing it wrong.
For my money the PA28 (the tapered wing versions) teach you to control your approach speed properly as they don't slow as easily with smaller flaps than the C172 and experience more ground effect with the low wing. 5 knots of extra airspeed has a much greater effect in a PA28 than it does in a C172.
Yes you are allowed to spin at least some model C172's when flown in the utility category, but they are a dreadful aeroplane to teach spinning in. You need pro spin aileron and they come out of the spin the minute you relax any control inputs.