I bought a small 16-oz cup for $2.59.
There's a definite vanilla creme (or creamy vanilla) flavor to the Frappe, more so than there is an Oreo wafer (and chocolate) flavor. To go with the (very) sweet and creamy concoction, there's just a hint of bittersweet coffee flavor at the tail end.
Appearance-wise, the whipped cream and bits of Oreo in the Frappe looked pretty good but the sparse sprinkling of crushed Oreos on top felt a bit stingy.
Nutritional Info - McDonald's Oreo Frappe - Small (413g)
Calories - 540 (from Fat - 180)
Fat - 20g (Saturated Fat - 12g)
Sodium - 170mg
Carbs - 82g (Sugar - 68g)
Protein - 7g