I shipped a UPS Next-Day Air package on 12-15-11. It arrived on 12-19-11.
The customer called and complained about the charges. I called UPS to get the customer a refund on freight charges.UPS told me there was a storm and they could not refund charges. So if there is a storm, Next-Day Air is not guaranteed.
I have dropped Next-Day Air from my website and I will try to talk any customers out of receiving their order Next-Day Air. Also, they will not guarantee Next-Day Air packages if their truck has accident.
Review about: Ups Delivery Service.