in the last 2 months or so, i've been lucky enough to have lunch at union sq cafe 3 times, blue water grill twice and tocqueville once. while all are good, i have to say the food and overall dining experience were inversely related --am i using that expression right?--to the crowds. BWG and Tocqueville both have a $24ish prix fixe, and USC--i believe--does not. USC is always jammed and the service sometimes suffers as a result. BWG is crowded but easier to get a seat and i think the food has been slightly better.
But the big surprise was Tocqueville--empty, quiet, civilized, delicious! i am promoting it because it was so empty i worry they'll stop serving lunch or close down or something.