Sega Game Gear
The Sega Game Gear was not the first color portable system as that honor goes to the Atari Lynx. It was, however, technically superior to the Game Boy in many ways yet never really was able to compete. The Game Gear had a pretty good game library though nowhere near what the Game Boy had. It was quite a bit more expensive than the Game Boy, particularly early in its life, had much poorer battery life, and was released several years later giving the Game Boy a market dominating head start.