The terminals numbering system is extremely confusing. Kindly add more signs.

Early in the morning of 1 August 2009, LaGuardia was evacuated because of a passenger carrying a fake bomb, resulting in huge delays:

http://www.cbc.ca/world/story/2009/08/01/laguardia-evacuted.html

LaGuardia has customs available for general aviation, but unlike EWR and JFK, it doesn't have a separate international section with customs lines, etc. As a result, it handles only domestic U.S. scheduled airline flights, as well as a few from Canadian airports that have U.S. customs preclearance facilities. A lot of its traffic is shuttles up and down the east coast and out to Chicago.

It was a huge deal for me when Ottawa added customs preclearance in the late 1990s, because then I could fly from YOW straight to LGA and take a cheap, fast taxi ride into midtown for business meetings, instead of having to fly to Newark and take a long, slow cab ride in, then try to bribe a NYC cabbie to take me all the way back out to Newark for a late afternoon flight home.

The best way into Manhattan is just to take a NYC cab. It's a pretty fast and reasonably cheap ride in if traffic permits.