Why don't more sites TELL YOU when your order will arrive?
Sure you can click to a site's shipping policy, and do the math in your head. But isn't that what computers are good for? Rote calculations?
Their instructions are clear. Chose this option, get it this day. That's all you need to do. Not only is this good service, but I imagine that they are often more successful upselling. They tell me in the header how much more I need to spend for free shipping. And if I want it faster, exactly when I will get it at what price.
Contrast that with a company FAMOUS for service - Nordstrom. They make very little attempt to tell you when the order will arrive, nor do they try very hard to sell you on increasing your order to get free shipping. You Need to click the "Shipping Methods and Charges" link
after which you get the shipping dictionary, so you can figure it out for yourself.