Of course, you are never going to cart around a 27-inch iMac Pro to use on your lap during a daily commute to the office. But you're also never going to buy a MacBook Pro for one weekend away ...
With the 24-inch iMac replacing the lower-end 21.5-inch iMac and the higher-end 27-inch iMac having finally ... B&H Photo, Best Buy, and MacMall (which is now integrated with TigerDirect).