Both Soy Milk and Almond Milk are good healthy milks to drink but Almond Milk is the healthiest milk out of the two milks.
Almond Milk contains more monounsaturated fats that are healthy for your heart than Soy Milk does and Almond Milk is also lower in calories than Soy Milk.
Soy Milk does contain more protein than Almond Milk though so if you need more protein I would go for the Soy Milk but it's good to drink both Almond and Soy Milk to stay healthy and reap the health benefits of both Soy Milk and Almond Milk.