I use the regular 3DS too. Not just for AC, but for pretty much every 3DS game. The only one I wouldn't recommend it for is DKCR3D, because it's actually way too hard to see your character.
I have the original (launch, so it's got the most playtime of all of them), XL, and 2DS, with the New on reserve- getting it Feb 13! The 2DS has taken over as my New Leaf system (it's about the only game I play in it now), while my original has been reverted back to my main 3DS- plays everything. The XL is my least played of the 3, both for New Leaf and games in general. Outside of helping with StreetPass, it hasn't hardly been used at all. I'm not too looking forward to having another XL (New 3DS), but maybe it'll grow on me, but personally, I LOVE the smaller systems, the screen size isn't really that much smaller than the XL's.