So I just got to Jabu Jabu and here are my thoughts:
It's definitely not a "minimal" graphics update as people were saying (you know, before it came out so they couldn't try it) and the 3D enhances it, but you're not really missing much if you turn it off. (in fact turning it off enables anti-aliasing so it looks much smoother)
The looking around the room thing is great at first, but it gets a little frustrating if you have the 3D on, because unless you can perfectly tilt the screen towards you as you continuously move the 3DS, your eyes won't keep the 3D image and you'll keep seeing the screen swap images with some dark regions moving across the screen.
Makes it real hard to aim with the slingshot, but I've gotten used to it and it doesn't happen that much anymore. You just have to learn to keep your head and the screen parallel when you're moving it around. Other than that, motion controls for looking is actually kinda more fun than gimmicky.