Works nicely on my S4 Mini running only
the stock Jellybean 4.2.2 (root'd), allowing me to have the best of 2 music players on screen at the same time, both of them functionable.
Sounds like TouchWiz 3.0 + Exynos - based phones are the only ones that support UI hardware acceleration using the GPU, along with NEON instructions, to minimize UI lag, while
stock Android may not get something similar until
Jellybean, which I suspect will be long after 4212 - based phones arrive.