The xl feels so much nicer to hold. The 3d sweet spot is a lot smaller though. I couldn't game for more than an hour or so on the original 3ds without my hands cramping up.
The visuals are indeed sharper but I'll trade that off for comfort. As much as I like my 3DS it does get a bit uncomfy for me after 30 mins or so. Having a play on my mates XL I thought it was a better fit for me.