not ready for everyday use. There is also no radio connectivity, since it has yet to be certified for such activity, and phone calls can not be made or received. The SD card reader is unstable and the touch sensitivity on the screen has not been calibrated. But as a web based OS, there already is a well developed ecosystem for apps, which is obviously important for developers.
This might not be unprecedented, but it is unusual. If you own the Sony Xperia E and have an interest in the Firefox OS, click on the sourcelink.
source: Sony, TheVerge via Engadget