I've been to the top of the Empire State Building, and the view from there is magnificent. The only downside is that you don't get to see the Empire State Building! The Top of the Rock offers the best views in the city and virtually all five boroughs can be seen from there. It was my second time up and I intentionally scheduled a time around twilight. It was my son's birthday and we wanted to see the sun set as well as watch the city come to life at night. It couldn't have been better. If you know when you're going to be in the city and want to go up, you can check published sunset timetables and plan according. You have a certain time on your ticket and you are not allowed up before that time. In this case, planning ahead can yield some great views and pictures, depending what you want your experience to be.
Lights start to come on in Midtown Manhattan around 8:30 p.m. (below) on a beautiful June evening.
Looking north from the Top of the Rock is Central Park, the Hudson River and New Jersey to the left, and Harlem and the Bronx are visible in the distance. One of the best man made views in the world!
The observation deck at the Top of the Rock.