I'll judge Rosati's by what they claim to be: an "Authentic Chicago" restaurant featuring pizza, italian beef, and hot dogs. I think they did a very mediocre impression of Chicago's classic food.
The thin crust pizza was my favorite: pretty crunchy crust with flavorful sauce and enough cheese (nothing too much but it was at least more than a national chain like Papa Johns. The toppings weren't as plentiful as I'd like. Each slice had two or three pepperoni pieces with a couple sausage bits. I thought the taste reminded me of a Chicago thin crust pizza but was not up to its level.
For the Italian beef, it was not comparable at all. Very below-average. Flavorless without copious amounts of either Au jus or giardiniera. The french roll was too soft and had no exterior crisp to it.
The prices are a tad high, but for a place that calls itself a specialty restaurant they are what you'd expect. Service is pretty fast and friendly. Overall three stars sums it up: Mediocre.