The video [below] shows the Gecko runtime along with some WebGL animations running smoothly at 60 fps (frames per second). The computer is definitely capable of running quite a few operating systems but, this particular port gives us a glimpse of the capabilities of Firefox OS.
The performance of the OS is definitely good for entry-level smartphone and being able to work on a computer with such specifications gives us a glimpse of what Mozilla and its partners have in store for future smartphone users. If the OS is this smooth on the Raspberry Pi, imagine what it would have in store when it is executed in the current high-performance processors and enough RAM.
The project by the Nokia Engineer, though on an experimental basis, indicates that the OS can perform quite well on an ARM 11 processor.
If you are currently having a Raspberry Pi, which recently saw its order limit shackles removed, and want to try it on your own visit his personal website here and download the .tar.gz file.