The usage is very difficult because of the slowness with which the interface responds to the touch. When scrolling the page, for example, the movement is jerky and does not reach the end. Only when you tap the screen again, the page suddenly move in the correct position. Another problem is related to the touch, like when you want to click. Firefox always react as if you did the long press (context menu on links and images, text selection, etc.). I do not think it is only a performance issue, because the P920 is a phone powerful enough. Pinch-to-zoom works perfectly and smoothly. Sorry for my poor English.