I bought iPod Touches for my 2 oldest kids and my wife last Christmas. So, this year, instead of buying $30-$40 games, they have been able to buy several $2 games throughout each month.
It's been a blast, the savings are starting to really show, and they even like the games better.
That's just what they tell you so you don't feel bad for getting them iPod touches. They secretly play Nintendo 3DS games at friends' houses.
No 3DS, but they haven't seen one yet, so who knows, maybe this Christmas things will change.
As in most things, you get what you pay for.
http://www.metacritic.com/browse/games/release-date/availabl...
They do aggregate scoring and have established themselves as the main way to rate "greatness" on PC and consoles, going as far as landing game directors a bonus if their creation gets a score above 85. They're quite valuable for iOS as well. "King of Dragon Pass" gets a 90 at MC.
Most critics review games based on what they are. So a simple jump&run game might rate highly if it's a truly original+fantastic one. I would suggest you go through the list - anything above 80% is a game absolutely worth your while - then see if the genre and complexity fits you.