Well, I'd say it depends on your travel patterns. Take a look at AA's services out of STL and ORD for your Midwest travels. To the east coast, I'm sure you can probably get to where you need to go through DFW as well. AA is a little week for travel up and down the east coast IMHO. But I think they'd serve you quite well traveling to the east coast from LA.
AA has managed to avoid reducing the valuae of elite qualifying miles so far as well. Take a look
here for AA's elite qualifying requirements.