The SlateBook has a battery life of around 7 hours, though your result will vary depending on how you're using the tablet. The keyboard has its own battery that can charge the tablet when docked, and using the two together nets you an additional 3 hours of battery life. Although such numbers are good for a laptop, the Nexus 7 and iPad both deliver longer battery life without the aid of external battery packs.
HP would have been better off just making either a laptop or a tablet; as a hybrid of the two, the SlateBook x2 offers the worst of both worlds without most of the benefits. As a tablet it doesn't have enough going for it to stand as a viable choice against the Nexus 10, Sony Xperia Tablet Z, or Apple iPad. The SlateBook could make for a compelling netbook replacement, but its relatively high price and unstable software mean that it is pretty much useless for anything other than Web browsing—a task you can accomplish for much less with a traditional PC or even a Chromebook. It's only a matter of time before someone makes a good Android-powered laptop, but the SlateBook demonstrates that we're still a ways off from that reality.
Sign up for CIO Asia eNewsletters.