The best reason I can think of is that 0.7.0 is finally Panther native, which means it was built with GCC 3.3. That should mean more compatibility/stability. The main reason I upgraded is because visual-py23, a 3D physics package for Python has made it from unstable->stable. Which was the only reason I was sourcing the unstable tree. Now I can go completely stable.
Also it comes with Fink Commander, I'm not sure if it was with previous versions, but I just discovered it, and it's pretty nice.