It was perfect for the Galaga-like level in my game. I only need to define a few control points to create a robust flight path for the enemy drones. The cool thing about the Catmull-Rom algorithm is that the spline passes through the control points.
Of course, you could do all of the above without SpriteKit. For example, for all of the rendering, you would simply write everything directly in OpenGL ES.
There are also cross-platform options, like Cocos2d-x [3] and Marmalade [4].
Finally, if you've read this far, you might be interested in reading my general thoughts and feelings from when I finished the game [5].
Cheers!
[1] https://developer.apple.com/spritekit
[2] http://www.raywenderlich.com/category/sprite-kit