Sizewise, what's most important is that neither the Surface nor the iPad 4 can easily be held with one hand; they're just too big. Encasing Surface's 10.6-inch screen is a 10.8 x 6.8-inch metal case, while iPad's 10.1-inch LCD is surrounded by a 9.5 x 7.1-inch plastic and metal enclosure. They also weigh about the same -- Surface tips the scales at 1.5 pounds while iPad weighs in at 1.44 pounds. We'd say that physical dimensions are a wash.
We salute Microsoft for its magnetic power connector, which mimics Apple's proprietary MagSafe technology. This type of connector couples with the main unit magnetically, popping off easily under stress rather than damaging components. Ironically, Apple does not use MagSafe on the iPad (it's reserved for MacBooks), opting instead for the all-digital Lightning port, an all-purpose port that handles charging, video output and numerous other communications duties. External controls are otherwise about the same. Both have power and volume buttons, a headphone jack, mic and speakers and a dedicated "home" button. Apple adds a combo mute and rotation-lock button.