With so many people buying new developments these days, how do you know the quality or the life span of the materials that are being installed in the project are top notch. At least with an older development, you can see by the condition of the products that after a few years of wear and tear, you see what is to be expected in the proceeding years of use.
Some drywall coming from the plants in China (Chinese Drywall) have been found to include phosphogypsum. Phosphogypsum contains radium and over time, this can increase your risk of lung cancer. The same can be said for the hard wood floors coming from the same area, which are on occassion a poor quality as well, the wood can contain a higher level of humidity than competitors and can develop problems over time.
On another note, every home has some form of mold in it, it's just that these days mold of course is a four letter word and as soon as you say it people react. Not all molds are bad, but in this case, with Chinese drywall, it's more than just mold.
Hope this helps