Republic has excellent food, is centrally located right on Union Square NW, is perfect for a mixed crowd of vegetarians and carnivores, etc. However, to enjoy this restaurant it is imperative that you go at the right time. Dinner? Forget it, unless you're going early. Weekends? No way. Basically, any possibility of rush hour and you should stay away -- the place gets incredibly loud, inconveniently crowded and obnoxiously scene. Banquet-style long tables and backless benches end up putting you uncomfortably close to neighboring strangers and serve up an inescapable eyeful of butt cleavage from surrounding benches. When the place is full, service is spotty and when the wait staff do show you can barely hear each other over the din...
Despite all these factors, Republic remains one of my favorite restaurants -- the trick is to go during the off-hours. The place is a ghosttown for late weekday lunches -- our company often goes there for afternoon business meetings. Staff are more attentive, food comes almost instantly, there are no volume issues, and the banquet/communal setup doesn't matter when you have plenty of space.
The food is wonderful -- heaping bowls of noodles, spices, meats... a relatively small menu but yet something for everyone. I know it seems ridiculous to recommend a restaurant for only off-hours, but the food really is incredible, and if you can avoid the crowds, Republic is still well worth a visit.