It's hard to make that call since Android is still in its infancy a far as gaming goes. But personally speaking, I feel like hand held gamers days are numbed.
I think Sony has already seen the light, which I'd why they have released the PSP phone. No, the game market for Android hasn't caught up with either Sony, Nintendo, or Microsofts game catalog. But in two years or so, I sure wouldn't bet money against them catching up to, and possibly passing all thee of them. At that point what would a parent do.... buy his kid a $250 'gaming only' device, or a $200 dollar gaming device that he can also use to call him with, take pictures with, video tape with, etc...
It's the age-old 'killing two birds with one stone' theory. The average age for kids with cell phones is dropping by the season. So why get them both a cell phone, and a hand held gaming device if you can combine the two? Now I do see the phone companies coming to one compromise to help parents swallow this pill a little easier. Because I know some people are thinking, "yeah but not all parents are going to want to have to pay $10 bucks for the extra line AND $40 bucks for a smart phone package".
To all of you who thought that, congratulations, that's an excellent point. Which is why I foresee in the very near future carriers creating an entire new plan specifically for gaming phones such as these so parents can buy one for their child and activate only the phone portion of the device, leaving the online gaming up to wifi connectivity. If/when the kid gets old enough to pay for the data plan, then it can be activated that way.
I've met with a lot of negative feedback concerning this theory of mine, but the way I see things going..... is inevitable really.
So to answer your question, for now I'd say if you like the 3DS, go for it.