Beauty dishes are interesting in that you get a very unusual catchlight... kind of like a donut. I had a pair and used them a couple times but stopped... preferred a softbox and diffusion panels. But I still have the Custom WB stored in my X.
They do limit the area that's lit... kind of like a spotlight.
I used a Beauty Dish and was really anxious when I bought mine. I used it quite a bit as fill but never really was that thrilled with it. Not really sure why, I guess I just liked some other modifiers better. I sold mine and don't plan on replacing it.
Thanks for all your information; looks like it would be especially nice for male portraits. I checked the elinchrom site and its a nice touch for ladies also, I guess it would take some getting used to. I ordered a small one, can't wait to give it a whirl.