So I bought one. Before you judge me let me defend myself a little:
I had a launch 3DS, just outside of the "get a ton of free games for nothing" program. My right shoulder button was dead and it wasn't holding a charge for longer than a day (maybe 14 hours) when in sleep mode, playing it required knowing where the power cord was at all times. I sort of just needed to buy a new system or do the tech guy thing and fix it (i hate doing that when it is my only system). The new 3DS, at this moment, is the same price as the "old" 3DS XL, so why not.
It is so much better. The 3d head tracking thing works in anything that isn't the Nintendo setup app. I have had a couple of friends play around with it and it works for everyone. There isn't a reason anymore to not have the slider all the way up as the system just adjusts to how it should project. If you suddenly move it will sometimes "snap" to the right focus, but that is for stupid sudden movements.
The faster processor is NOTICEABLE. Noticeable as in Fantasy Life loads menus, new maps, and saves the game jarringly faster. That might sound odd, but when you have played a game for 25 hours and sudden the timing on everything inside of it suddenly changes it is ultra weird. Monster Hunter 4 (only ever played on the new system) might as well not have loading time. When you are getting into the game the longest parts are hitting a button to skip the load screen itself.