3DS XL = 3D and larger screens, no "New" capabilities.
New 2DS XL = Larger screens and "New" capabilites, no 3D.
I personally don't like the 3DS XL model 'cause it feels kinda cheap regardin' build quality compared to the other ones, The New 2DS XL was the first "New" system I got, but I like better my New 3DS nowadays, I just like the smaller size.