The food is always super fresh, looks gorgeous and tastes heavenly! Several non-vegetarians I've taken to this place have said that the burger was the best they ever had -- not just best veggie burger, but best burger, full stop. The food is made using seasonal organic produce, so the menu varies between seasons.
Worth noting is also the overwhelming friendliness of the staff (very unusual for Belgium!). They'll even happily tell you their recipes.
My favourites include the cashew balls and the delicious filled sea-shell pasta, and of course the burgers. Give the aryurveda drinks a try, too, they're more than just lemonades.
Cons: the seating is a little cramped