It seems a bit weird to me. I assume that Mario, his partner, and all of the NPC's and enemies would "pop out." On one hand that seems rather distracting, and on another it seems somewhat cool. Ultimately I believe that it'll be more distracting than interesting, since your eyes will be averted towards the characters when your trying to do something in the overworld (like look for a hidden item). --- "They're NOT DOLLS. They're ACTION FIGURES. WITH REAL FIRE-PUNCHING ACTION." ~Francis. Super Paper Mario.~
Someone that was on the 3DS board said he got to try it out about a month ago. He said it was the most intriguing of the games he got to play. Apparently it felt kind of like a pop out book.
He also said the number that shows up when you land on an enemy flies out at you and it's really distracting. He suggested turning the 3D off in battle but leaving it on in the overworld. --- Ya dun goofed