So far, for me, FedEx has still been $2-3 cheaper, but I don't have a business. Just shipping 3-4 items a week right now cleaning out my old things. Since your warning, I look on Google Maps to see if the destination looks remote and, if it does, I use USPS. For a business that would probably be very annoying and not worth the time.
I wanted to buy a video game guide book from amazon or ebay, 1 book shipped here was going to cost more to ship than its value (>$15USD). What the hell. Stop having stuff that I want, USA!
Just had 2 DVDs complete with cases shipped from Taiwan on the 18th, and I received it today. USPS made me sign for it and write my address (it's a new thing). Cost the folks in Taiwan less than $5 for this "express, premium" shipping. I know I should get over it, yet it still amazes me every time.