Besides offering obvious image quality improvements compared to HQx, its also 60% (!) more efficient, something very important for portable Android devices.
It also scales really, really well on itself.
This is a sprite with an xBR filter in 1x, 3x, 9x and 27x(!)
Comparison:
HQx (notice the heavy aliasing on the coin, Yoshi's nose, Mario's hat and the blockface)

xBR (aliasing on coin, Yoshi, hat and blockface gone. Also, no more blurry background! Woo!)

Again: even though xBR is the better method, its computationally 60% 'cheaper' on the processors.
Relevant link: http://filthypants.blogspot.nl/2012/03/ ... ilter.html
Pretty please with sugar on top?