This is a widely debated topic with no true answer. Which business card finish you choose is ultimately up to you.
Glossy cards can feel more polished and more attractive, particularly if you use a design with lots of colors or include an image.
Matte cards eliminate glare and can feel more modern than glossy cards. Matte cards typically feel better in the hand and allow the opportunity to add texture. You should choose a matte card if you want varnish.