I believe that specific emerging market currencies, bonds, and stocks are going to be the best performing assets over the next 10 to 20 years (and specific commodities will be some of the best performers over the remainder of this decade), however, in the short term there are always major set backs in markets, which (if you are bullish on the long term fundamentals of an asset class) should be happily welcomed as buying opportunities.
I believe that China will own this century in terms of economic growth, just as the U.K. did in the 1800's and the U.S. did in the 1900's. That does not mean it will be a straight and steady climb in their markets and their economy each and every month. The U.S. experienced the panic of 1907, a major recession in 1921, the great depression in during the 1930's (and so on and so on) before becoming the greatest economy in world history during 1950's and 1960's. Every major sell off during the last century provided a long term buying opportunity for those that understood the bigger picture
Today we have tremendous fear around the world that China's economy will implode, something I disagree with. What is guaranteed is that there will be huge set backs in their financial markets, which could be caused by events such as a shadow banking freeze described in the video below. Longer term investors should look at a panic sell off in China's markets as a welcome opportunity to add to positions in great businesses.