They operate to AA standards (for better or worse) using slightly smaller aircraft -- CR9s and E175s/190s versus 737s and A320s. Most passengers don't perceive the difference. On BOS-ORD you are liable to get an E175 aboard which "first class" is a 2+1 layout, "Main Cabin Extra" 2+2; some prefer this arrangement to a mainline aircraft as there are no middle seats.

On an approx. two-hour sector like this there will be drinks and hopefully wifi. I can't say about food, snack basket pass, etc.