I'm very surprised at the quantity of low reviews for this place, as I think it has the best sushi in the city and is one of my favorite restaurants in Pittsburgh. Yes, it is pricey but I think it's safe to assume that the quality and freshness of fish here is a little bit higher than the stuff you see at your local Giant Eagle.
I definitely suggest trying the Wasabi Tobiko ($4 per piece). Such a unique piece of sushi, and one of the reasons I've been counting down the days until my next visit to Umi.