The performance does definitely depend on the complexity of the animation.
Small icons like the hamburger menu, wish list heart, hamburger arrow, etc run at 60fps. Even the main Lottie logo (http://airbnb.design/lottie/) that has pretty complex trim paths renders at ~60fps.
Masks and mattes are the feature that incur the largest performance hit because they require allocating a bitmap (8 bit for mattes and 32 bit for masks), rendering to them, then drawing them back to the canvas.
That's not an answer to how does it perform. For example if the hamburger goes from 4ms/frame to 12ms/frame then lottie is crazy expensive, even though it's still "60fps" in the test app.
What is the actual end-to-end cost? Have you measured it at all?
Masks and mattes are the feature that incur the largest performance hit because they require allocating a bitmap (8 bit for mattes and 32 bit for masks), rendering to them, then drawing them back to the canvas.