The M900 is the last in the line-up of three new smartphones that Acer showed off at the Mobile World Congress 09, but it differs significantly from both the F900 and the X960 that have gone before it.
The M900 has two main features that help it stand out from the smartphone crowd. The first and perhaps most striking is its extremely large screen. Measuring 3.8in across the diagonal it's one of the largest we seen on a smartphone (matching that found on HTC's Touch HD). The display's resolution of 800 x 480 is also impressive and means you've got a lot of screen real estate to play with which translates into less eye strain when you're using it for long periods to view and edit Word documents or Excel files on the go.
The other key defining feature is the slide out keyboard. Similar to handsets like the Sony X1, HTC Touch Pro2 and Nokia E75, the front face of the M900 slides away from the main body of the phone to reveal a full QWERTY keyboard.
The keys are relatively large and each line is angle away from you so as to provide a raised edge for you fingers to fall on. But although the keys are reasonably responsive, it's not all that easy to get up a decent typing speed mainly because the keys are lined up tightly next to each other. As a result it's difficult to distinguish between individual letters when you're tapping away at speed with your fingers and thumbs. Compared to the keyboard on the Touch Pro2, the one on the M900 certainly comes off second best. Also, unlike the Touch Pro2, you can't angle the screen upwards once the keyboard is open, which is a bit of shame.
The large screen and keyboard have a significant knock-on effect on the overall size and design of the handset. To call it big-boned would be putting it mildly. Even by the standards of keyboard-equipped phones, this one is big and heavy. You'll definitely be putting this in a jacket pocket rather than a shirt pocket. The ungainly styling doesn't help matters either with the buttons and camera poking out from the case rather than being mounted flush like on most modern handsets. In fact, the whole design approach gives the handset a somewhat dated look and feel.