This obviously depends on your taste, but yes, arugula tastes good in smoothies! It does have a stronger "green" flavor compared to other classic greens included in smoothies, but I find it adds a nice kick to my morning drink. Make sure to include plenty of fruits that are full of natural sweetness to balance the peppery flavor of arugula. Also, arugula goes well with tropical flavors, which works out well with the banana and pineapple in this recipe, but mango is another good choice.