I'm not a huge fan of the BK Veggie. First of all, I don't particularly like white bread, just a personal preference. Secondly, I think the patty would be quite good if it was fried on a grill; I think it would be pretty tasty if it was crisp on the outside. Cooked in the Microwave or on their broiler thing, it kind of stays soggy. Also, for a patty that clearly has all kinds of good stuff like grains and mushrooms in it (you can actually see the bits), I don't think it has much flavor.
But then I've never had a good meal at the Burger King in Boise, not even as an omni. They don't clean or change their fry oil often enough, and everything produced there seems to have that dirty oil flavor to it, even the burgers. The BK Veggie that I had in another state when traveling was better, still not great, but better. Overall, I'd rather have a bean burrito at Taco Bell.