Tried the new kosher pizza place in Center City, called Blackbirds. I didn't think I would be crazy about vegan pizza, but it is awesome! Tried it for the first time last week, and then took my family Saturday night. They liked the sandwiches, but absolutely loved the pizza. Our favorite slices were the mushroom and the nacho (with avocado and jalapeno). They use a cheese called Daiya - it does have a different consistency that is more noticeable on plain slices, but not very noticeable on slices with toppings. And the garlic bread is the best I've had anywhere.
The space is very casual, even for a pizza store, although there is plenty of room to sit. I have not yet tried the salads, so that will be next. But I definitely recommend this place.