Hello,
I went the ATP route, but not because I wanted to go to the regionals. I was trying to get all my ratings here in Alaska, but the weather was not cooperating. So I decided to attend ATP because of the pace, and they have housing.
I could not be any happier with ATP. The instructors were great, the planes were in great shape, and the cross country phase was a great learning experience.
However if you live near an airport with good flight training available, I would go the FBO route.
The only bad part of ATP is Sallie Mae.
If you have any more questions, feel free to ask. BTW, I went to the Sacramento location.