I hadn't been in the United States for over 6 years, so I hadn't experienced the tightening of regulations since the tragic events of September 11th, 2001. I had heard certain horror stories (for example J. Karjalainen, Finland's Bob Dylan, had been detained without reason in Missouri) so I was certainly sceptic about going through there.
Even though I did have to travel for more than 24 hours, I faced no difficulties. The American Airlines staff on board and on the ground was generally very corteous (however, their fleet is really old) and the border and customs officers were very professional, so there was no problem at all. It takes much, much longer than transiting in Europe (that's how afraid they are) but it did go smoothly.