I've never been to Una (line-up is too long) or Double Zero (avoid downtown when I can), so I can't compare Without Papers to much else in Calgary.
A bunch of my friends arrived on a Sunday night. The restaurant was about a quarter full but there was only 1 server for about 5 tables. As a result, service was really really slow. I couldn't really get upset as it just seemed the restaurant was understaffed. The pizza was great - thin crust with delicious toppings. I tried the Hutch - which had lots of spicy meats and a good layer of cheese. Personally, I think WOP is better than Famosa, particularly in the crust and topping ratio. The mark up for some of the wines was a bit high for me but not outrageous. At least the wine selection is pretty good but limited. Great space - and I love the set-up. Great place for a date or a party. Can't wait to go back and try the mushroom pizza.