Hmmm... I think the Gameboy..Advance was the worst one because it was basically a uglier Gameboy color. The only difference was they made the games smaller and added more pixel like graphics..
I once had a really old , Atari like hand-held system, i don't remember who it was manufactured by but it was giant, like almost the size of ps2 slimline, so that it didn't really have good graphics anyway.
Ok serch up the "virtural boy" by nintendo it was supposed to be in 3-D but it was sooooo lame and the colours were red and black only,It was hard to play it for long cuse it made you're eyes hurt.
I think game boy advance was the worst.And the Ds is ok but i hate it pretty much too. Nintendo really needs to make better higher quality games. I mean brain games, who wants more school work and learning.