Eagle outsources maintenance in CMI and CLE. They stock parts and do relatively heavy scheduled maintenance tasks. ABI is an AMR subsidiary that does heavy checks but is not TWU. MQT is now Eagle/TWU as is XNA. There is a base in West Virginia that does CRJ work, I believe it is a factory shop. BNA, as an EMB factory shop also does EMB work. I imagine that there are others that I don't know about.
I personally don't sweat out station maintenance that does light checks and stocks the appropriate parts, i.e. lamps, tires, brakes, etc. However, when they start stocking parts that we don't have at the hub station I start to wonder.