The advantage of OLED is its power consumption. In addition to E-ink, The OLED maybe is the most energy efficient screen. The 128x64 OLED screen is very cool. This module is equipped with the most comprehensive software support, you can effortlessly draw the pattern on this screen what you want. When you look it like the all-metal Xadow clock , you know I did not lie to you.
Xadow is a though small but perfectly formed Arduino(TM) compatible board series containing several modules. It's a kit extremely suitable for space-sensitive projects such as wearable devices & arts designs, which have higher request on size, weight and flexible cascade connection.
You can find more modules here.