Ok, I tried the demo, I'm really disapointed by the 3D.
I must say I always play my 3DS game with the 3D slider set to the maximum and always love it. I think it adds a lot of information to the visuals and when I deactivate, the graphics lost a lot in readibility, obviously for games like Mario 3D Land that benefits a lot from 3D to the gameplay, but even for more simple games to (animal crossing, mario & luigi dream team bros). I see very easily 3D pictures ( stereograms, 3D movies, 3D games, ... ) and can really see the details and defects in depth informations.
Golf video games are one of the kind of games that always missed the depth information and could benefit a lot from 3D graphics. It can potentially add a lot to the estimation of the distances and to the precision of terrain elevation, mainly on the green.
I was really hyped by the release of a Mario Golf 3DS. But when I launched the demo I was instantly disapointed ... The intro movie seemed "flat", the 3D was activated, the slider was se to the max, but it was as if I put it to 10 - 20% ... I thought it was only the intro movie and I started a course.
Ok, my slider was really set to the max, the hud elements pops out of the screen, but the ground, the sky and Yoshi looked all flat, there are very little depth between all these elements and you can't really see depth information of the terrain ... 3D is totaly useless in this game, it mainly just separate the hud to the scenery ...
Nintendo missed a lot with this inexplicable choice ... There's really no reason to do this. They missed a great opportunity to make a game that could demonstrate the advantages of 3D video games. As if they don't care about 3D anymore ...