Is that model similar to the Geeksphone Peak? I have a Keon and it is a bit slow, but the Peak is just as fast as (maybe even faster than) an iPhone, re. launching and switching apps and overall responsiveness. Quite impressive for a HTML5-based system UI.
Regardless, Firefox OS is not actually competing with Android/iOS right now, it's goal is to bring smartphones to the very low end of the market and push open web technologies at the same time. It seems to be working.
No, the ZTE is not at all similar to the Geeksphone Peak. It's even slower than the Keon -- it has half as much RAM as the Keon, and only 512 MB of internal storage (I think the Keon has 4 GB).
Regardless, Firefox OS is not actually competing with Android/iOS right now, it's goal is to bring smartphones to the very low end of the market and push open web technologies at the same time. It seems to be working.