I've always had trouble deciding between blonds and brunettes...
Specifications for Kasteel Tripel: 11% ABV, serve around 50 degees (F), can be cellared for long periods (proper conditions, of course).
Specs for Kasteel Brune: 11% ABV, serve at 55 - 58 degrees (F), cellarable.
The Brune is actually a quadruppel and rates higher on Beer Advocate than the Tripel. If you like floral, fruity beers with a hop finish, then you will like the tripel. If you like a more balance, complex, dark fruit sweetness then have the brune.
They are both 11% ABV, so make sure you don't have to drive
