I made steak Dianne with mushrooms and no meat. It was pretty good, but gave me bad gasI sometimes go for the veggie options to give them a test try. Safeway recently had one of those all inclusive kits in their deli, basically all the ingredients for a recipe neatly packaged with instructions on how to make it. I saw a mushroom burger one and thought it looked good. I forget the actual secondary ingredients, but the main ingredient was Portobello mushrooms that you put in a food processor and mince em up.
I have to say it was really freaking good, not as good as a beef burger though. The problem is... Although some of the veggie options are good, I'd rather have the real thing than the alternative.