What is low VOC paint?
Generally the durability is considered to be just as good as the older paints. The VOC-Free paints still have less color-selection (at least last time I looked), but that's been changing as demand increases.

The building I work in (in the U.S.) just completed a LEED-Platinum renovation, and used all VOC-Free or Low-VOC paints. Some of the special purpose paints were not available in VOC-free yet, but low-VOC paints covered most of what they needed (including paint for a metal roof).  

I was impressed at how much less they smelled when I stood next to a painter with an open tray of paint for several minutes before realizing he had fresh-paint out (I was disappointed that it smelled like someone had painted a week before until I realized he was doing the touch-up painting right then).  In the first year we haven't seen any issues related to durability.