The main issue with FirefoxOS was the performance(of the devices and perhaps also the OS itself). I had the first firefox phones(I think the brand was ZTE) and

The main issue with FirefoxOS was the performance(of the devices and perhaps also the OS itself). I had the first firefox phones(I think the brand was ZTE) and they were basically rubbish(i.e. they had a 1sec or more lag). I would take a Nokia 6600 over that any day. Mozilla tried to market it as a low cost alternative but nobody wants low cost rubbish. You are better of with a feature phone. I think the biggest mistake was the reliance of the OS on javascript. It was dead on arrival or better said from start.