I'm pretty confident that I'll get mine in a few days, since I already have the copy of Silver Marches that I ordered at the same time (though according to Buy.com it shipped the day after I ordered it, and according to the shipper, it shipped two days after I ordered it), but I wish the tracking info from the USPS was more useful.
UPS or FedEx will give a reasonable update every day, so I generally figure that I'll actually have an item no later than a day after it gets to California, and can guestimate. With Silver Marches, the postal services' tracking system said that 'we have been notified for pickup' until the day I got it (and then it switched to arrived in San Diego).