Yogurt is much healthier for you than sour cream is.
Sour cream contains quite a bit of fat while yogurt does not so that makes yogurt the healthiest of the foods to eat.
Sour cream is healthy though just like yogurt but sour cream can be fattening while the yogurt is not.
Yogurt helps your digestive system as well and can help prevent constipation while the sour cream cannot prevent constipation.
Yogurt also contains only around 18 calories per serving which is quite a bit less than the sour cream of the same serving contains.
Eating yogurt regularly help keep your digestive system working properly and may even prevent some diseases such as cancer.