"It looks cool" is common the first thing said of the Apple //c. And indeed that is its most striking feature. Designed as the first foray in the Portable Apple 2 world, the machine was very small, the case designed by FrogDesign, the same company that would later design the Apple IIgs.
Essentially an unexpandable Apple IIe, the //c had some pretty nice stuff; MOS 65c02 running at 1mhz, 128k RAM (Expandable to well over 1 meg with third party upgrades), built in 80-column capability, built in 5 1/4 floppy drive (with a SmartDrive connector on back for additional disk drives and even hard drives), two serial ports and mouse/joystick port. The processor could eventually go as high as 8mhz with upgrades like the Rocket Chip.
Though Apple had never intended it to be mobile, Prairie Power corp even designed and sold an 8-hour battery pack for it, and several companies offered LCD panels that would plug in to its RGB connector.