For tweening operations LeanTween is over 5x faster than iTween in my tests! In the included example you can see LeanTween animating 1,500 boxes Running at 1.86ms frame intervals versus iTween’s 9.94ms. 5x faster speed is great, but the huge advantage is that there are no sudden drops in framerate. Unlike iTween where in my example you can see it drop down to 1.53 frames per second (or 652ms to render a frame), and this is on a Mac Pro desktop machine! On mobile it would be much worse (comparison with iTween on mobile).
LeanTween’s low overhead and excellent speed is achieved by it’s smart reuse of objects, which avoids garbage collection and the associated frame drops. There are also many gains by having a single For Loop that executes code in a very optimized manner.
The speed difference is shown in my other project FPS Graph:
I was prompted to write this post, not because I hate iTween, it’s a very well thought out package, but I am in shock that iTween is the most downloaded tweening library for Unity. Particularly with most developers using Unity with an eye on mobile development it seems a waste to hand so many precious CPU cycles over to something as simple as tweening.