Every airline has irregular operations from time to time, but the telling point is how they treat the customer during that event.
Our flight from Munich to Iceland was delayed at the end of September causing us to miss our connection to Seattle. When we landed in Keflavík, our phones immediately notified us of our flight being rescheduled for the next day. We went to customer service where they gave us vouchers for transport to town, a hotel room, and meals. They also informed us we were eligible for compensation under EU261 for 600 euros each and provided the link to make the claim.
We had an extra day in Iceland with expenses covered and returned home the next day. 5 weeks later (the time they told us to expect it to take) the compensation money was deposited into our account.
There was duty of care and compensation without hassle or challenges. I appreciated this from Icelandair.