Emmy, a while back I posted a similar query regarding getting a computer or playstation for my six-year-old son. As a result, I decided to hold off until christmas, when he will be seven-and-a-half.
However, he was given a gameboy (his father's idea, not mine!!) for christmas when he was five-and-a-half. Initially he didn't do loads with it. The instructions seemed quite complex to non-techno me, as well as being difficult for the average 5-year-old to read. He needed adult help to get going. Once he'd mastered the basics he began to enjoy it, though it only really became his number one toy a year later.
For me there are pros and cons.
The cons are:
Time lost hunched over gameboy, replacing more physicaly acitive, intellectualy varied and social pursuits. So I have to limit gameboy hours and ensure he gets plenty of the above.
Loss and expense: being so portable, the gameboy and games are small, so very easy to lose. We found a gameboy carry case is a must - and a rechargable power pack rather than endless batteries.
As with all his toys, for my son part of the pleasure of the gameboy is showing it to his friends, and sharing it. This is fine if there are adults in close proximity, but we have encountered problems when the gameboy is shown to strangers, especially if they are older than my son. Gameboys are rather desirable to 12-year-olds too!. Sadly it is not unknown for games to go 'missing'. Apart from speaking to the parents you can't do much if a child flatly denies they have the game and you weren't there to witness what happened. At the worst, a touch of intimidation and bullying is can be involved, when a crowd of bigger boys come up and insist on looking and holding the gameboy in a 'friendly way'. My son has lost two games so far, one at his after school club ( after much pleading we allowed him take it there once or twice), one with a crowd of children outside our front door. Whether they were lost or stolen isn't clear cut, but he's now banned from taking the gameboy out unsupervised.
The pros are:
He enjoys it. It keeps him quiet, still and concentrating. Not things that used to come very easily to my son. It is probably marginally better than sitting passive in front of TV. It helps stop him being bored on long car journeys.
For me, a huge bonus is that it an instant and portable way of gettng him to be good! Sometimes we take it when we go out, if a lot of travel in involved. But it lives in my handbag and that's where it stays if my son has an 'attitude problem'. And generally, the threat of confiscation of the gameboy for a day or so has a magical effect on his behaviour......