With its second bite at the Ultrabook cherry, Acer looks to have hit the heights. This time, instead of a half measure in the shape of the Acer Aspire S3 with its hybrid SSD/HDD storage solution, the Acer Aspire S5 goes straight to the top of the Ultrabook tree by taking the title as the thinnest of the lot.

At 15mm at its thickest point, it's understandably feather light and, although the exact specs have not yet been revealed, Pocket-lint would guess at around the 1.2kg mark from our hands-on time at the Acer press conference at CES 2012.

The magnesium/aluminium alloy chassis itself, though, is fairly understated. The finish is matte but by no means brushed and combined with the modest dark paint and gentle curving lines it rather has the feel of a less showy version of the Samsung Series 9. Even the ports are hidden away behind the MagicFlip I/O panel at the rear of the device - something of which Acer's president of Personal Computer Global Operations, Campbell Ken was particularly proud.

When it came to squeezing the button on the top right of the keyboard to kick the servos into action, it was a little too keen to close itself straight away and its possible that there could be some issues here. We'd also hope that the flap is sensitive enough to notice when there's cables connected rather than crush them or the chassis of this presumably rather expensive machine trying to force itself shut. We'll have to wait for the full Acer Aspire S5 review to find out.

Otherwise, the keyboard is of the isolated chiclet style and the trackpad a single, external button-less affair. The 13.3-inch display is bright and clear with the top end, next generation Intel Core processors at the helm. And, unlike the S3, this time, it's a purely SSD scenario.   

Connectivity-wise, it has all the latest speeds available with USB 3.0 and Thunderbolt slots under the I/O panel along with an HDMI port as well. It comes with Dolby Home Theater tuning, as we saw on its predecessor.

The Aspire S5 will start shipping in Q2 2012. There's no word on pricing but expect to be paying four figures. Those past the decimal point not included.