Get an XL. Matte finish, bigger buttons, bigger screens, and improved battery life.
Buttons are about the same size, I think, but they're different and better.
-Better buttons (including the system buttons and the 3D slider)
-Better stylus placement
-Far, far more comfortable
-Significant reduction in reflection on screens
XL is a much better machine, but I do however think the original 3DS looked better. The XL looks a better in person than in images but it still looks kinda cheap and dated whereas the OG 3DS looked nice and pretty modern, especially the ones with the three tone design.
If only something could be done about that 240p display.... ugh... 3D was such a waste to put in there, it really stunted what it could have been from a more practical perspective.