The 2.8in, 480x640-pixel TFT LCD touch screen is decent enough, though not particularly distinctive. It's bright and clear enough to render pictures well and with a reasonable degree of clarity.
The touch screen resistance is generally okay, though in common with many Windows Mobile 6.1 devices, it does have the odd sticky moment.
Like HTC's Windows Mobile devices, which hide their Windows origins behind their TouchFLO 3D interface, the DX900 uses Spb's Mobile Shell (though it's the older, clunkier 2.1 version rather than the latest 3.0).
The idea is to get away from Window's fiddly menus and enable you to navigate more with your thumb than the stylus. In this it's only partly successful.
Keypad is disappointing
It works fine for the basic menu, diary and messaging, but other aspects are less than stellar – the phone keypad isn't as good as it should be, with small keys, and there's no haptic feedback to help brickie's thumbs like ours find the mark
Acer's own Easy Keyboard also proved almost impossible to use without a stylus, since the keys are so tiny.
Even flipping the device on its side didn't help, since the keyboard remains the same size – with blank space on either side
Movement around the menus isn't the quickest we've seen – the Samsung 533MHz S3C6400 processor is only backed up by 128MB of RAM, and when we had several apps running at once, delays were obvious.