Built like a tank, with a lovely retro design, the X100 is comfortable to grip and shoot. The front switch allows you to toggle the viewfinder between optical and electronic displays. There's also a ring on the lens for manual focus.
Despite the retro look of the front and top, the back has the typical layout of a digital camera. The AE button brings up metering choices, while AF lets you choose the AF point (when in the default area AF mode). The View Mode button switches between the LCD and the viewfinder. The jog dial Command Control in the upper right triggers a zoom view in manual focus, as well as duplicates functions of the dial such as program shift. And I love having a raw override button.
But one of my biggest frustrations with the camera's design is the horrible command dial/navigation control. It's nearly impossible to press the menu button without hitting one of the other buttons and vice versa.
In addition to a great manual aperture dial on the lens, the X100 has shutter speed and exposure compensation dials; in its default configuration, the Fn button brings up the ISO sensitivity options. Unfortunately, if you want to switch to auto ISO you have to dive into the setup menu, and while it's easy to save and configure custom settings, you also have to jump into the menus to select them.