The biggest advantage of inverted forks is their flex, or lack there-of. Conventional forks tend to flex and twist more than inverted forks. Also, inverted forks have a lot less underhang to grab onto the sides of ruts. That used to be the only differences. Now days almost everyone has dropped development on conventionals, so technology-wise they are way behind inverted forks. However, they can be made to work quite well, and in some cases are prefered.
Scott Summer's is running conventional forks because he prefers the extra little flex in the rocks and roots off road. Everyone always talks about how the KDX shines in narly off-road conditions, thanks in a large part to the forks. Now, stiffer springs are almost a must, and revalving can make a big difference. But unless you are hitting up the motocross track all the time I don't think you'll find a real big advantage to going inverted, especially for a trail rider / every-now-and-then-racer.