I received my CIME from FSI in May 2001 and finished the (now defunct) ASA program in August 2001. While I was at FSI, I met several people who had transferred from other flight schools, and usually they had good things to say about FlightSafety in comparison to those other places. The school does a good job of teaching you, but they are on the expensive side, if not the most expensive. They will prepare you for the airline environment, and you'll do much more mult-engined flying than at many flight schools.
I'd recommend getting your PPL and building some hours first. In the 141 Flight School environment, there is a syllabus for every lesson and almost every activity (ground, flight, whatever) generates paper work. The rigid structure can be stressful, but most of the students there try to help each other out.
I don't mean to start any battles with people who have gone to other flight schools, but this is what I heard while at FSI. I don't know anything specific about Pan Am in Fort Pierce, but the FAA examiner I flew with did not have many good things to say about them. I've heard that the instruction at ATP is not as good (in fact, my partner in the ASA program was from ATP and did not succeed in completing the program.) My roommate, who came from ATA in Orlando said that they were a "mess." I also heard from many that the students at Comair were very competitive with each other. Now, I can't vouch for the accuracy of any of these comments, they are just what I heard from other students who had experiences with these other schools.