I flew DL a couple of weeks ago for the first time in years and really liked it. I also flew two segments on US. Both DL and US were a pleasure compared to the 2012 version of UA.
I'm on the road next week and starting out with UA but will be flying DL (intentionally) on the way back.
I've already booked two cross country segments on US next month.
Getting rapidly disenchanted with UA. Needs to get its act together soon.