Hot Hardware published a review on the HP Spectre X360 Ultrabook: Sleek, Sexy, Convertible @ HotHardware.com A quote from the article:

HP used the Mobile World Congress event currently taking place in Barcelona, Spain to launch what may be one of the company's most exciting notebooks ever, the Spectre X360. Like the previous-generation Spectre, the new X360 is a thin and light premium, multi-mode convertible ultrabook , but HP has paid special attention to almost every detail on this new device and improved upon its predecessor in virtually every way. HP worked closely with Microsoft and its hardware partners to choose the right components and optimize the software on the Spectre X360 and the company made some practical decisions with the design and materials used in its construction that have clearly paid dividends on our opinion...

 HP Spectre X360 Ultrabook Review: Sleek, Sexy, Convertible @ HotHardware.com