A problem with all these advanced acceleration techniques is beam quality. I'd worry imperfections in the microfabricated device would cause this to degrade.

A problem with all these advanced acceleration techniques is beam quality. I'd worry imperfections in the microfabricated device would cause this to degrade. Imperfections become increasingly important as the device is miniaturized; in a 1 micron device, an offset of a single atom's width is .01%.