I was on a DL flight that was delayed for mechanical reasons, then switched to a different aircraft, and finally cancelled.

We were provided overnight accommodations by DL. Not long after I checked into my hotel, a CS agent called me to make sure I was happy with the room (I was) and to tell me I’d be getting a $100 check in the mail to cover incidental expenses. It arrived within a week.

Great customer service, in my opinion.