It's hard to describe what makes it such a nice portrait film. I'm using it in large format for contact prints, so it's not really a resolution issue. I think it's a spectral sensitivity issue--skin just looks different with Ektapan. Maybe the gradation in the midtones is also somewhat smoother.
I didn't find it as satisfactory for landscapes, but maybe I would need to use it more to figure out what situations called for it. Since it's out of production, though, I'll probably keep my remaining sheets for the application I like it for.
It is capable of expansion and contraction and prints well on Azo, but since I'm using it in the studio almost exclusively, I always process it normally and control contrast with lighting.