Acer's S5-shaped go on the Ultrabook gravy-train is a three-pound, 13.3-inch lappy that'll turn on instantly, toting a sleek onyx black magnesium-alloy cover, Thunderbolt port and an SSD for easy flinging. Improving on the design of the S3, it's the world's thinnest Ultrabook, measuring just 15mm and feels significantly more premium. Sadly it's not all gravy: it's got a scratchy, shallow keyboard which we're not sold on. What we do love is that the ports drop down from a motorized back cover -- Thunderbirds fans out there will adore it just for that.
Dell's been waiting to show off how thin it could make a device and the XPS 13 didn't disappoint. The company's first Ultrabook tapers from 18 to 6mm and is made from aluminum and carbon fiber -- and with the attendant weight loss. The entry-level unit's got a Core i5 CPU, 128GB SSD, 4GB RAM and a backlit keyboard. It reeks of understated quality, even though it's only $1,000, but the port selection is pretty basic: it doesn't include an SD card slot, which we think is an unforgivable crime in the year 2012. Corporate IT buyers who need to be conscious of roaming-employees' luggage allowances: this is going to be a go-to product.
Samsung's revamped Series 9 shouldn't be on this list, because it's not an official Intel-sanctioned Ultrabook. That doesn't stop us giving it honorary status because of its extreme thinness. The company spent last year listening to user feedback from the original Series 9 and threw out everything customers hated. Gone are the soft touch finishes and launch buttons, so the dimensions are more like those belonging to a 12-inch device. The 15-inch Series 9 is also special, mostly because it's the only laptop that thin with that large a display.
Lenovo's IdeaPad Yoga is another device that isn't branded as an Ultrabook, but that's what it is: no tablet would weigh three times that of an iPad 2. The 17mm thick flip-over device can be used as a laptop, tablet or kickstand-tablet for movie watching. You'll want to watch movies on this thing, too: it's got a 1600 x 900 IPS multitouch display, unheard of in a device of this caliber. It'll retail for around $1,000 when Windows 8 arrives, but even the prototype models scream of quality. None of these other devices ship with a touchscreen and is cheaper than the less capable HP Envy -- if we were buying one of these devices today, our money would be on this device.Dana Wollman and Jon Turi contributed to this report.




