For 1-day mail delivery of certified check, should I use Post Office or United Postal Service.? Who's best?

Asking for collective wisdom from my Yahoo friends. I have a certified check that I want mailed Overnight. For reliability, where would you go: to a local UPS store, or the U. S. Post Office? Thanks much!!!

For price and reliability I'd use the US Postal Service. You can call 1-800-ASK-USPS and determine if the mailing office can guarantee overnight delivery to the addressee's zip code. Unless it's a very rural area, the guarantee is next day by noon or 3pm.

USPS has a on-time delivery performance score of 97%.

If you go to a UPS store you are dealing with a franchisee who may or may not give you the correct information.

Each service can be problematic in the length of time it takes to reach the destination.

UPS.

I personally use fedex express. Post office in least reliable.

I live in a rural location and overnight mail by the postal service is not an option. They "call" it overnight, but it actually takes two days. FedEx is also not an option here, UPS has never failed me --- I wouldn't trust anyone else. :-)

It depends on the location & day of the week. USPS is good for Express mail & so are others however, if it is a rural location it would not get there as quick as you may hope with any delivery company. Many small post offices do not deliver on Sunday. USPS can type in you destination zipcode & let you know cut off times for overnight.
PS If you do not sign the signature waiver & no one is home the carrier will take back to the PO for next day delivery. If you sign waiver, it will be put in their mailbox.