high index lenses are good if you have a strong prescription.........I think they have a 1.67 refraction level, so they can come out really thin if you have a strong thick prescription........
also, if you have strong astigmatism, (+/- 3.00 and over), the high index will give less distortion.
I have heard Nikon are great..........they are a great brand name, and also cost a lot........am I correct?