Well... I wouldn't discount what they are saying. Although in my testing, I didn't encounter the 'unplayable' issues, they could still be having legitimate problems based on the fact that they could have different firmware or any other number of things could cause it. That's why I take feedback. If everyone having problems could tell me exactly how it's behaving with no embellishments, I'll look into it.
BTW: DaveC: The author and I have surmised that the GP2X's complicating factor is it's joystick, and implementing case 2 for the GP2X took many core changes. A joystick that sends button events is far from ideal, as most joysticks send axis events. Given these circumstances, we are doing our best to accomodate the GP2X. If you would like to take a look at the source and tell me how you would implement the joystick differently, I'd be very interested to see the changes.