Recently I've gotten myself into a dilemma of sorts. I was introduced to the world of matte boxes for film and 10 stop filters, and since my video tripod can't take any of those sick rigs with follow focuses, I decided to get a clip-on matte box that was light weight.
The tokina 16-28 can't fit any clip-ons that I know of, but a 17-40 can.
What I'll lose with the 2.8 I'll gain with the ability to put on creative filters. But IQ wise, I'm not so sure of that. Specifically at f/4 (or 2.8) and f/8-11.