Yeah, the hugh meaty ones. And these ones are even bigger than the usual.
I've marinated and broiled them before, but not grilled them.
They're good even broiled, but they should be great cooked over charcoal.
Supposedly you can even eat 'em like a burger - with the bun and all the fixings. I don't think I'd take 'em that far, but they are pretty favorful.
Portabellas are wonderful on a good quality cracked wheat bun with lettuce, tomato, red onion and catsup!! Though I really have never thought they taste like steak, no matter how much OB tries to convince me of that.