Heh, it's funny I was writing the below post while GAF was down, and it's about the topic you brought up.
I never thought I would be saying this... but I may have found games that I prefer playing on the smaller N3DS. This is not good (because now I want to own both sizes)
I've always been vocal about my preference for the XL's screens. The improved pixel density on the smaller screen never came close to outweighing the better feeling I got from the larger screens (for what it's worth I always play in 3D, and I think it plays a role in my preference for the larger screen, in most games).
Let me preface this by saying that the Sega 3D Classics are probably my favorite thing about the 3DS's entire library. I'm crazy in love with them.
I tried 3D Super Hang-On on the soon-to-be-my-nephew's regular sized 3DS, and predictably I felt the smaller screen was too underwhelming and the game almost lost its appeal to me. Then I tried 3D Streets of Rage 2, and as I usually I do I started gushing about how cool the game looks in 3D; the beauty of these 3D remasters never gets old to me... but then I realized this seems to look even better than I remember it from my XL... could it be?? After some more play time and more gushing. I pulled my XL and booted the same game to compare... hmm, yup, this game definitely looks nicer on the smaller screen! This is a first for me.
Next I tried 3D Sonic on both systems, and again, I like how it looks on the small screen more. I'm guessing the same will be true for Shinobi and the other side-scrollers. This is a bittersweet revelation to me, because on the one hand I welcome any way that would make my favorite games look ever better, but on the other hand I know without a doubt that I prefer the XL for the vast majority of the system's library... except these few gems, but they are my favorite gems. So now I feel like I need to keep two systems. I don't have money growing on trees Nintendo!