I use applesauce when baking cakes. I use the same amt of applesauce as I would oil. I like how moist the cakes turn out this way. I don't notice a flavor difference, but if you do, play around with using oil and applesauce, maybe half of one and half of the other. A few tips I've learned...1) measure the applesauce in a liquids measuring cup, 2) use unsweetened applesauce so you don't add more sugar to the final product (thus increasing the calories).
You might want to take the time to google your question (unless someone more in the know provides good info for you) to learn more about it. I've read for example that you probably don't want to use applesauce when making cookies as they will turn out more cake-like and less crispy.