Re: Fantastic sound quality.
Results are probably due more to quality PA system design and implementation more than mic choice alone. The skills of your audio operators come into play in a big way too.
NT5s are generally quite hyped in the top end and require can require some pretty drastic EQ. As long as there's not too much else blaring around stage they can work well.
Hereby & forthwith, any instrument with an odd number of strings shall be considered broken. With regard to mix levels, usually the best approach is treating the mandolin the same as a cowbell.