The Nokia app requires a longer exposure time, encompassing multiple shots, which basically means that anything moving is a no-go. The quality of its pictures is theoretically superior, though, because the depth effect comes from the photos themselves, and not a simulation.

Google's version, on the other hand, works with only a single photo, so it's more versatile. It may suffer issues with quality, though (arising from the difficulties in accurately extracting depth values from a 2D image). That has yet to be seen.