I am not usually one for touristy bus tours, but being alone I wanted to see as much as possible and not feel intimidated having no idea how to get around NYC. I picked up the tour outside the Empire State Bldg. It takes you all over the city and the map is easy to follow as the bus makes its way through the traffic. I LOVED being able to sit up top and just gaze and "gaga" over the tall buildings. Being on top also gives riders an almost 360 degree look around and really helped orient me to the city and where things are. After spending my whole life (34 years worth) seeing New York City on TV and movies, it was amazing to me to see it up close and in real life. For those more cynical and professional travelers, this may seem naive but I really enjoyed it. I am usually the kind of person who prefers off the beaten path non typical tourist stuff. The Gray Line tour guides were all very informative, many were funny and most were extremely friendly and helpful. They pointed out all kinds of interesting things that I never would have known if I were just walking around or taking a taxi.
Traveling alone, I thought the bus was a good way to get around as well as to chat with other tourists and get my photo taken so that my pictures actually reflect the fact that I was there! It eliminates the obviousness of me standing by myself on a street corner with a map and a guidebook shouting TOURIST!
I purchased the "All Loops" tour for $50 which included all of Manhattan as well as a nighttime tour over the Manhattan Bridge to see the skyline at dusk- beautiful.
The daytime loops are split into upper and lower loops with transfer between the two in Times Square. You could also purchase the Loops separately for $37 if you were only interested in doing one. I recommend both. The pass was good for 48 hrs and there were many places to get off and reboard later like Battery Park, Chinatown, SOHO, Museum Mile, Rockefeller Center, Harlem, Times Square, Central Park, and more. For someone who is familiar with NYC and a veteran traveler this might not be so great.
I would recommend this to travelers who want to see a lot in a short time or for those who would like a good overview for the start of a longer trip.