I use both concurrently (with 2 bodies obviously) giving me the flexibility and added focal range of the zoom and
the extra stop / bokeh when I need/want it. Also, with the 1.4 TC, I still get 280/2.8 when I must position myself further from my usual courtside action.
While slightly larger than the 70-200/2.8 II, the 200/2 still fits (unattached) in my ThinkTank Digital Holster, giving me the added flexibility of having 3 lenses (the third being the 135/2) on my 2 bodies and a dual Black Rapid strap system.
I simply prefer/require the extra stop in most arenas.
The fast focus ring and AF stop buttons, along with the blazing fast AF are nice extras
I love my 70-200 (like my mother) but LOVE my 200 (like my WIFE).
As for portraits, it is a bit bulky for street / event shooting, but for sessions on location where I can control distance to subject, it is an excellent choice.