I have a P250. It is just about the same bike with 90%+ of the mechanicals being the same as the P250S. It has the 16 inch wheels and does great in suburban traffic situations.
As for durability, I have over 33,000 KM on the bike and the only issue I have had, other than wear items (brakes, CVT belt...) is the muffler. It failed during an 800 mile ride I made earlier this year. Kymco's are known for being durable machines. You can see my picutres from my touring rides over the years. The Ride to RoM was an 800 mile 3-day weekend ride.
I know many of Piaggio's larger wheeled scoots had a fuel pump issue related to the ethanol in our fuel and were subject to stalling and other problems. I don't know if it was only the China manufactured bike or it was both the Italy and China made Piaggio brands. The SportCity 250 is a mainland China made bike with Piaggio engineers at the manufacturing facility.
I considered the SC when I was buying in 2008 but I love my Kymco. I don't regret buying it. I bought mine used and am the third owner.