I've tried the ShroomBurger (twice) and I've gotta say that I liked it! The portabella mushroom was cooked perfectly and the cheese (filling) was excellent. I'm only taking off 1-star, because they tend to cook the burgers a bit longer than I like. I know it's allways about Risk for the establishment, but if they would cook the burger a bit closer to medium than well, they would offer a truly juicy burger... and I would offer a 5-star rating.
By the way, the sides are always great... and so are the desserts.