With Marriott, I haven't had many significant service issues, but my sample size of stays over the past two years has obviously been smaller. I had the cancellation issue in 2020 (caused by faulty IT) at two properties - both were taken care of promptly by the property themselves (one gave me a very nice suite upgrade on my next stay there when I was a Gold). Most others were taken care of in a satisfactory manner by the property immediately by the property. In cases where points weren't delivered properly, Corporate has never given me issue. I had one significant issue where the property refused to provide proper remedy (security issue). I called Corporate, and the property called to offer proper remedy within the same day.

Now, I also haven't had major service issues with Hyatt, but the only stay I have ever had to walk out on was a Hyatt. To their credit, my concierge and the property worked together to make things right.