I see a lot of complaints about the new UA here on FT, but I have had no reason to complain myself. Perhaps because I come from PMCO and am perhaps used to lower standards. But so far so good. I have only had 3 UA issues this year.

1. Misconnected in ZRH to a UA flight due to a late inbound from another *A carrier. When I got to the gate the UA aircraft was still there, but they had closed the door. Disappointing to see "your" aircraft there and no flexibility to reopen for a 1K, but such is life. They rebooked me on LH for a 3-hour delay. Not perfect, but I didn't complain. Sh*t happens, and in reality it was not their fault, it was the other *A carrier for being late. I did not ask for nor receive compensation, and I am okay with that.
2. Was unable to pick up a EWR-ZFV ticket of a UA codeshare "flight" because the Amtrak machine could not find my reservation. Amtrak desk was closed, Amtrak agent on the phone was unable to find any reservation, UA agent on the phone was trying to help until my phone battery died. Out of options, I purchased the Amtrak ticket with $, and submitted to UA for a refund. UA apologized and sent me 3x the cost of the Amtrak ticket in UA voucher, as compensation. I thought that was very fair.
3. And then this TK issue, which they also resolved quite well.

So all in all, I am happy with UA. There are glitches and failures, sure. No one is perfect. I don't complain a lot nor do I expect a lot in compensation (perhaps I was conditioned by CO) and to me UA has been very fair. May it stay this way.