What hand held game system should i get for my little girls?

I have a 5 and 6 year old, both girls, we currently have a VSmile and they both play it but my 6 year old is a bit to "mature" for it. My friends son has a DS and she plays that real well but i don’t know, that may be to much of a system for a 6year old, especially because i want her playing educational and G rated games only. I have seen the hand held VSMiles and i think that would be great for my 5 year old as she just barely turned 5 and she has a minor learning disability and she still struggles with some of the V Smile games but is getting the hang of it. Here is my problem, if i get them two different systmes my youngest one ALWAYS gets upset that her sister has a different one then she has. They both picked out MP3 players for their birthdays and each got a different one, and they both PICKED the ones they wanted, and of course in the end my youngest daughter was upset hers wasn’t the same. I don’t neccisrily want to get them the exact same things so i am going to "talk up" whatever system my youngest gets in the weeks prior to christmas so that she gets excited about the fact that that certain system would be "perfect for her because….." i just want to make sure i get the right things. What would you recommond and why? What do your kids play? Any advice would be wondermous!! THanks!!!

You can get simple learning games for the DS as well, it is for the younger kids plus it has a touch screen that blows kids minds usually. But there’s tons of little girl games all over ebay, walmart, everywhere so you cant go wrong with a pink little DS, besides that theres not much of a market for and other brands the PSP is way to ahead of there age, so check into the V smile or the DS.