But it seems the touch screen is not that sensitive. I can see there is a setting in the code for the precision of the touch library, and a calibration one. I've calibrated it and tried various precision settings. But sometimes it seems that it just doesn't register my touches. Sometimes on the example drawing app I touch it and there is a single dot, sometimes lots of dots. On the example with buttons I sometimes had to tap it multiple times to get the buttons to register a tap.
Any idea on how to improve the sensitivity? Is this an issue with the hardware itself, or likely to be a software/library issue?
Is your outer screen tight against the LCD?
I had received one and it's outer screen had a slight raise to it.
If this is the case for you tell them and they should exchange it if the purchase was recent.
I have got a similar problem and I solved it by the following way :
I have solved the problem by canceling, in the UTouch.cpp file, the line 113 :
/* if (!((temp_x>max(touch_x_left, touch_x_right)) or (temp_x==0) or (temp_y>max(touch_y_top, touch_y_bottom)) or (temp_y==0)))*/
It works fine and without, for me, any side effect.
But it is not a very nice way.
Write to sainsmart and they will send you a modified version of UTouch that solve the problem.