After seeing the few Chowhound reviews and Asimov's NYT review on Itzocan Bistro, I finally went up there with a friend of mine to check it out. Let's just say I will definitely return and continue to refer my friends to this place.
Itzocan Bistro is located on 101st & Lex, and they take CASH only, so be prepared. They do serve wine, beer and sangria - I really liked the sangria ($5/glass; very refreshing and light). I had the pumpkin and shrimp soup with a dollop of chipotle cream - HUGE portion ($5) as a starter. My companion had the goat cheese flan ($6) which was rich and eaten with mixed greens and small slices of bread. For entrees, I had the filet mignon special ($15) which was served with a Bordeaux reduction and porcini mushrooms, potato gratin and asparagus -- executed beautifully, but I think I will have to try the more Mexican-style entrees next time. My companion had the ancho chile-rubbed duck breast which was very good as well (also $15). I tried a Kahlua flourless chocolate cake which was like most chocolate cakes at other restaurants (couldn't really taste the Kahlua); next time will try the pineapple creme brulee, pumpkin creme caramel, or the Kahlua pot de creme which have been recommended. My friend had the chocolate pear tart which was very nice. Desserts were $5 each.
Service was very nice and efficient. Atmosphere was casual but not sloppy - will definitely return!