I bought a Game Gear back in the day, but never really got that much use out of it. Realistically, you could only use plugged in to the mains so it was only practical to take it on journeys where you knew there was a socket waiting for you at the other end.
Good/bad points.
+ A powerful handheld that's capable of producing graphics and sound that are respectable even today
+ Some great little games: Sonic, NBA Jam, Shinobi etc.
+ Clear, bright, sizeable backlit screen
+ You can hook a TV tuner up to this and have colour TV no prob
- The battery life is appaulingly low
- You need eight batteries to power this mother. EIGHT!
- It's way too big. Yes, I can hold it my hands. I can hold an Xbox in my hands, too, but that doesn't make it a handheld! This thing is a brick.
- The unit itself is poorly designed. The d-pad is comfortable but too loose, same for the buttons. You just don't feel right holding it (although that might have something to do with the enormous weight & size)
- It has a few good games, but not many. Most are genreic platform crap that were plaguing most consoles back in the day.
Plus my screen is brok0red. It's playable, but a few lines and dots have blacked out. I still buy games for this when I see them at a decent price, but I wouldn't actively search them out.