How do you cook/consume portobello mushrooms?

I am trying to eat mainly raw foods for a few days, as I have previously mentioned, and I am loving portobello mushrooms! Last night, I marinated them in balsamic vinegar, rosemary and garlic and then put them in the oven for 25 minutes.

Do you eat portobello mushrooms raw? Are they any good like that?

I am thinking I will probably lightly grill them tonight but am looking for a good marinade (nothing processed, or from a jar/bottle really) ... something I can make at home!