The 3D did have a somewhat spotty feel-- the pretty watercolor backgrounds had no real feeling of depth, and some scenes seemed more 3D than others. ("I Just Can't Wait to Be King" was one of the best parts, because its fairly simple, cartoony animation translated well into 3D.) Also, some of the faces and bodies were slightly distorted by the 3D effect. In particular, Mufasa's face looked oddly bloated. Most bright red (the sunsets, the fire) had a peculiar retina-burning effect that didn't look quite right. And finally, I thought the rain at the climax of the movie was too in-your-face-3D and obscured what was happening, but the kids liked it and thought it was well done.
Overall, though, it was a terrific experience.