Both companies are great. However I had a great expience with Nikon this summer. They replaced a scope on a rifle that blew up on me I never thought it possible but their no fault warranty is real. Now I am not sure Leupold would do that.
I have a Redfield and it is nice and clear as are all my Nikons. They may be clearer than my Vortek Viper that was alot more money.