Just got a 3DS XL and did the system transfer. Only problem is that it looks like this was a used system that was being sold as new... I really didn't think about the signs that I saw until I had already started the transfer process (signs: starting up right into the main menu before doing the transfer, i.e. no language set, date set, etc.; it already had internet connections in there... named Colin; and after I started the transfer I saw that it was named donut. DONUT.)
Sufficed to say, I'm going to go to Best Buy to yell at them. Biggest problem I have is that I have to wait another 7 days before I can do another transfer, otherwise I'd lose everything I have. So, I'll transfer it back to my original 3DS next week, return the used XL, and get a NEW new XL. And then I'll have to wait ANOTHER 7 days to even use the new XL. Bluh.