I second nymag. Also, while not a replacement for yelp, Per Se, keeping up with ny.eater.com will ensure you know of all the interesting/amazing places to eat/go out.
Word of mouth really only works if you live there, not so much if you're just passing through. And the time you really need a site like yelp is for all those times you're just passing through place and want to know who will do you a good pizza.
That's my use case for yelp like sites anyway. When I'm at home I go out for dinner on avg. once or twice a week or so and go to a new restaurant probably less than 1 time in 10, so my need for restaurant reviews is quite low. I also have plenty of other local sources for good reviews when I need them
When I'm traveling I eat out basically every night and visit a new restaurant pretty close 100% of the time. On the whole I have much greater need for a site with reviews of restaurants in not my home town than in my home town, and that hardly seems niche to me.
