Personally, I just try to buy as many as possible when I am back home. I have a few really bad experiences even with Durex branded ones that I have bought here and find the ones purchased back home to be far more reliable. Can also get those special ones that are laced with benzocaine on the inside that make you last for ages, for some reason Durex won't sell those in China.

If forced to buy any in China, due to the sudden emergency need to get a 3 pack or something, I tend to find that the Jizzbon ones to be more reliable and comfortable than other brands. That's just me though, every guy has their own preference.