Hi, 

I recently bought the 3DS and am happy I did so. The 3DS is smaller and more compact with it's flip open screen, and offers a bit more protection from scratches. If your worried about feeling dizzy or younger children playing on the 3DS, you can always adjust the slider of the 3D effect all the way down to decrease the intensity.

At the end of the day it all comes down to what you can afford. I went with the 3DS XL model, because I wanted to cover all bases and make sure I wasn't missing out on any features. I thought if I went with the 2DS, I'd probably end up regretting it later on down the track. I also felt the 2DS looked a bit bulky and childish.