Nine-Patch Drawable vs Shape Drawable. Which should be preferred?

Question

My co-worker and I developed two apps in parallel, each with similar styling. The main view background of these apps is a radial gradient. He implemented his as a nine-patch image and I did it with a shape drawable. Both generate similar and acceptable results.

So my question is, which should we use? Are there are trade-offs between memory consumption and performance? I imagine that the image could take time to load, but that the shape drawable takes more time to draw (due to calculations). Are these then stored in a cache and those penalties only happen the first time they are displayed or are these issues on-going???

Shape Drawable:

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <gradient
        android:startColor="#003472"
        android:endColor="#000034"
        android:gradientRadius="350"
        android:type="radial"/>
</shape>

Nine Patch:

Answer 1

Shape drawable is great for gradient kind of images with simple constant color changes. On the other hand, 9-patch images are great for images with lots of detail, constant color in streching regions.