AMR's MO is to buy up local operations, give everyone new uniforms (including middle management), buy new rigs, and quietly collect a bit off the top as long as the operation is profitable. not a lot of corporate BS. That being said, one operation might be a tight-run ship with good staffing, happy employees, strong union, and supplies...while another might be a real poop-show where you get treated like a warm body with an EMT card. Some have 911/IFT, some are strictly IFT. Do your homework locallly.
BUT: AMR is a giant corporation with all the benefits that come along with it. Generally on the higher end of local pay scales, 401-k, benefits, ability to transfer (nationwide), and also they have a FEMA contract and probably local disaster coverage contracts.
As a new EMT I would take any* job I could, and AMR would probly be a good one.
*within reason