1. Preheat oven to 400 degrees F. Brush the bottom and side of a 9-inch springform pan with some of the melted butter. For crust, unroll phyllo dough; cover with plastic wrap. Remove one sheet of phyllo and lightly brush with melted butter. Place a second sheet of phyllo on top, placing it at an angle to the first sheet; brush with butter. Repeat with remaining phyllo sheets one at a time, placing each at an angle to the previous sheet to form a circle and brushing each with butter. Using a wide spatula, transfer the phyllo stack to the prepared pan, carefully easing it into the pan and allowing some of the phyllo to hang about 1/2 inch over the edge of the pan. Make two slits in the center of the phyllo stack for steam to escape.
2. Bake in preheated oven about 8 minutes or until phyllo is light golden brown. Cool on a wire rack. Reduce oven temperature to 325 degrees F.
3. Meanwhile, drain and chop artichokes, reserving 2 tablespoons of the marinade. Set artichokes aside. In a large mixing bowl, beat cream cheese with an electric mixer on low to medium speed until smooth. Add feta cheese, dried oregano, and garlic powder; beat well. Add eggs; beat just until combined (do not overbeat). Stir in artichoke hearts, the reserved 2 tablespoons marinade, and the green onion. Pour mixture into crust-lined pan.
4. Bake cheesecake for 35 to 40 minutes or until center is soft-set and edge stays firm when gently shaken. If necessary, loosely cover the edge with foil the last 10 minutes of baking to prevent overbrowning. Cool in pan on a wire rack. Cover and chill for 2 to 24 hours.
5. Remove cheesecake from pan. If desired, let cheesecake stand at room temperature for 30 minutes to bring out its fullest flavor. If desired, garnish with fresh oregano. Cut cheesecake into wedges. Makes 14 servings.
6. *Note: For a lower-fat version, substitute fat-free cream cheese for the regular cream cheese.