Thanks for the feedback guys, I ended up caving and picking up the black XL on my way home. What really pushed me over the edge was learning that Gamestop has a 2x trade-in bonus on hardware right now, which means I can get $100 credit for my original model. Couldn't pass that up. Also amusing was that the three Target reps at the counter all said something like "We have those in black? I might have to get one now." I have no idea what took Nintendo so long to release this model here.
Anyway, I've only played around with it for an hour but yeah, it is immediately more comfortable and just clearly a much better designed, better-looking, better-feeling piece of hardware. Now more than ever I have a hard time believing anyone at Nintendo thought the original 3DS's angular, chunky design, with its sharp shoulder buttons and annoying row of select/home/start non-buttons, was good design. I'm not much for conspiracy theories but if anything was designed for planned aesthetic obsolescence it's the original 3DS.
A few observations I noticed that I haven't seen mentioned a lot of places -- the color temp of the XL screens seems significantly warmer (yellower whites), not that this is super noticeable unless both systems are open next to each other at the very white home menu. The XL's screens also seem dimmer than the original's overall, which also doesn't bother me since it's not like I ever played at maximum brightness on the original. Also, is it me or does the XL actually have worse speakers than the original? Again, not super concerned with the quality of the built-in speakers of a portable console, since we all know the only way we're getting decent audio out of the thing is with headphones.
As for nitpicks, I can't believe this thing doesn't ship with the charging dock. Instead I had to order it separately on their spare-parts website for $26 shipped. I knew what I was getting into here, but still, how cheap can they be? What can that chunk of plastic possibly cost them, a dime? Also, I kinda miss the telescoping metal stylus of the original, but that's personal preference.
Anyway, good news to anyone waiting for a new model to come out: Now that I bought an XL, Nintendo's sure to announce a new version sometime soon!