It is not quick enough for moving objects, but for static or with compositions with very slow-moving objects, it should work wonders. But one key advantage over the Lytro camera is that with MEMS the image taken is at full resolution.
There are others doing work in the field too. Stealth startup Pelican Imaging, for example, has been quiet for quite a while, but at MWC showed a working Lytro-like solution with a Qualcomm Snapdragon 800 chip. It combines images from a lot of small, cheaper lenses that allow for focus adjustments after the image was taken.
That is a different approach than what we have with MEMS, but it also opens a world of possibilities where you can use a single sensor with multiple lenses that are set to work at a specific depth and again achieve focus at all points of the image or selective focus after the image is taken. Pelican’s first camera should be coming out soon.