I place several orders a year with Midway. When I order they estimate arrival at 10 days to 2 weeks, which sounds excessive considering most of the other companies I order from can get the stuff to my door within 4-5 days of the order.
But the Midway orders always arrive much sooner than what they tell you at first, within 5 or 6 days. I think they are just playing it safe and would rather say it's going to take longer than it does.
As far as the USPS, my stuff shipped that way is ALWAYS here when their tracking says it will. And fast too, usually within 3 or 4 days.
Fed Ex is good too.
UPS screws things up a good 70% of the time. My orders will either get lost in Phoenix for several days before moving on, or the drivers will deliver the package to one of my neighbors, I guess as long as they leave the box in the general vicinity that's good enough.