I recently left Eagle before the sale announcement, but I can speak to the general conditions at Eagle. If you don't mind being an FO for a loooooong time, then it is not a bad place. As for the future being better or worse, I think a lot depends on if, and how, the divestiture of Eagle occurs. But until that becomes clear, speculation is speculation.
As for corporate culture, it is not the best. But then is any airlines'? I think AMR sees it as being beneficial to have every group mad about something, or perhaps worried about something. You will be a number there, but depending on what base you are in (e.g. LAX or LGA) the chief pilots really are willing to help you out. Generally speaking, great pilot group, and I know I learned a lot flying with some great guys (and gals).
Be prepared to fly a lot on reserve. But you may not spend much time on reserve also. Staffing has not been good for some time at most bases. Before I left, the company basically admitted that they were not upgrading as many people as previously planned because of a lack of ability to fill the right seat with new people.
Good luck.