We did express walk off for the first time this past September. I think we are converts too, it was amazing!
It was also great because we were in the first 'batch' of ships allowed back into PC after Ian, so there were six ships in port that morning (and at least a couple of them weren't scheduled to be). Although we had a rental car reservation we were nervous about getting stuck in long lines/traffic and/or not being able to get our car. So we did express walk off, were in line for the first rental car shuttle and had our car within minutes. Very stress free!