iphone 4S- has anyone had anyone problems? (Shanghai)

Hi my name is Colleen

I want to bring my iPhone 4S that I bought in Canada over to Shanghai but I am wondering if it is a good idea..

I was wondering if any other expects who have bought their iPhone 4S in another country and have brought it over to Shanghai have had any problems with sim cards, or bricking of their iPhone...

Thank you so much for your help! Just wanted to know if I should look into buying another phone other than an my iPhone 4S