[nubiannupe]

Well, I can't tell you anything about the business dealings of Model Express. Website looks interesting enough, though... (might have to buy something from them, myself).

As for Priority mail, this is what the U.S. Postal Service says:

Priority Mail is First-Class Mail weighing more than 13 ounces and, at the mailer's option, any other mail matter (including regular First-Class Mail) weighing 13 ounces or less. Matter mailed in USPS-provided Priority Mail packaging is subject to Priority Mail rates regardless of how the package is reconfigured or how the marking is obliterated.

Priority Mail generally offers 2-day service to most domestic destinations. Often used to expedite matter mailable as First-Class, Periodicals, or Standard Mail. Priority Mail envelopes and boxes available at no additional cost at post offices.