The Asus ZenBook Flip S rivals top ultrabooks with its sleek and lightweight chassis. This is despite it being a two-in-one convertible that can work either as a tablet or a laptop. Such convertibles are often heavier because of a glass touchscreen, or thicker because of the 360-degree hinge design.

In fact, the Taiwanese PC maker touts the Flip S, which is just under 11mm thick, as the world's thinnest 13.3-inch convertible. It also weighs a handy 1.1kg, achieved by the use of aerospace-grade aluminium. Yet, it feels solid, with hardly any flex despite my best efforts to bend it. My exertions, though, did leave plenty of smudges on its matte metal body.

To accommodate its tablet form factor, the volume rocker and the power button are located at the side. Also found here is a pill-shaped fingerprint sensor that is fast in logging in to Windows 10. However, it is only slightly recessed, making it difficult to locate initially by touch.

Its touchscreen is bordered by narrow bezels on three sides. The glossy-finish surface is reflective, but viewing angles are wide. The 1,920 x 1,080-pixel screen resolution is not as crisp as the higher-resolution displays on premium laptops, but adequate for a 13.3-inch size.

The keyboard is unsurprisingly shallow, but I am impressed by the tactile feel of the keys. There is also ample spacing between the keys, which probably helped me achieve a fast (for me) typing speed of 75 words per minute.

The Web camera is not something I usually pay attention to, but the one on the Flip S deserves a mention for being terrible. With its low resolution of 640 x 480 pixels, videos look blurry, with plenty of noise. Even budget laptops now sport 720p high-definition cameras, so it is incongruous to find such a poor camera on a $2,500 computer.

Also falling short is the included stylus. It has just 1,024 levels of pressure sensitivity compared with 4,096 levels for better models. Hence, it does not feel as responsive when I vary the amount of strength to draw a thinner or thicker line. There is also a discernible lag while I was using it. But at least Asus is not asking consumers to pay extra for the stylus.

I have more positive feelings about the other bundled accessory - a USB Type-C mini-dock with a USB Type-A connector and an HDMI port. With the Flip S having just two USB Type-C ports (no Thunderbolt 3 support), this dock is very useful and is small enough to easily fit in the pocket.

The Flip S sports the latest Intel Core i7 processor - with four processing cores instead of the usual two - as well as a 512GB solid-state drive. Apps open promptly and Windows 10 feels responsive. The Flip S scores 3,286 in the PCMark 8 Home benchmark, which is higher than the Dell XPS 13 (2,989) ultrabook.

Its battery stamina is less impressive, at around five hours in a video-loop battery test with the brightness set to maximum. In comparison, the Dell XPS 13 lasted eight hours. This result was expected as the Flip S's 39 watt-hour battery is much smaller than the 60 watt-hour battery on the XPS 13.

Vincent Chang

•Verdict: Asus has nailed the design and portability for this device, minimising the downsides of the form factor. Battery life, however, takes a dip because of the relatively small battery.