You can prints from slide film every bit as well as with negs, but prints from negs are usually cheaper. Slide tends to be a bit sharper and more saturated, but the difference is fairly marginal these days if you use a good printer. Neg film has far more exposure latitude and is thus much more forgiving of exposure errors. You can get an OK print from neg film underexposed by at least a stop or overexposed by two. If you are after skin tones there are purpose made portrait neg films available from a number of manufacturers.

Velvia isn't too good at skin. It produces artificially strong (over saturated) colours. It is mainly used by landscape photographers, in which role it is superb.

David.