I will agree with you that a concern of all of us long term Delta loyalists has been the degradation of the Delta "brand" by the usage of codeshare partners, regional airline partners, etc. You, apparently, are in a market where you honestly seldom get to experience "the real Delta Air Lines."

If you lived in a "real" Delta market, I think you'd have a different opinion -- but I do understand where you're coming from. Delta is not perfect, but it is generally good these days and is certainly getting better.

The OP is based in PIT, and I think his situation would be very close to yours. I think he should just stick with US. Hopefully, he will so that he won't have to spend all of his time chasing customer service solutions like you have to do.