The Dell XPS 18 joins the Asus Transformer AiO and the Sony VAIO Tap 20 in the growing portable all-in-one market, and Dell reckons it has the march on its rivals – the XPS is both slimmer and lighter than its competitors.

The XPS 18 is around 20mm thick, and it weighs 2.1kg – making it 300g lighter than the Asus, and less than half as hefty as Sony’s 5.1kg VAIO. That’s especially impressive considering a battery has been crammed in too  - if the XPS 18 can live up to Dell’s claims of five-hour battery life, it will double the Sony’s longevity.

Like the AiO, the XPS can be fully detached from its stand. Dell has fitted a couple of kickstands to the rear so the XPS can be propped up at a couple of different angles when it’s away from its base, and it uses a magnetic connection to re-dock with the stand when you return the device to its desk. Dell’s pre-production sample sees the Windows button and company logo in the wrong positions, but we’re assured this will be fixed by the time the XPS 18 launches.

The good-looking Dell follows the XPS blueprint with a glossy black bezel and dark matte plastic, and it’s a sturdy bit of kit – there was barely any give across the rear panel.

The Dell outdoes the Sony’s 1,600 x 900 panel with a 1,920 x 1,080 touchscreen, and we had few complaints about its brightness or quality during our short time with the AiO. Dell has ensured its machine will stand up to the rigours of home use by using Gorilla Glass, although the company’s representatives couldn’t confirm if it was the first or second version used.

Under the hood, several specifications will be available: the base model will use a dual-core Pentium processor, but high-end machines will run with Core i7s. They’ll all use Intel’s HD Graphics 4000 core, and storage duties will be handled by hard disks or SSDs.

The model we tested used an Intel Core i5-3337U – a low-power Ivy Bridge chip running at 1.8GHz – alongside 8GB of RAM. This should be enough to make Windows 8 feel snappy, but that wasn’t the case on the XPS 18: Windows 8’s homescreen and app store were sluggish to navigate, and there was even lag when opening basic Explorer windows in Desktop mode. We hope Dell will fix these issues with driver updates before release.

The left- and right-hand sides are home to speakers that pumped out good-quality sound, and there are two USB 3 ports. Dell includes a Bluetooth keyboard and mouse in the box, and the stand itself is impressively versatile, tilting forwards to a vertical base and upwards to a horizontal position.

Dell says the XPS 18 will hit stores on 16 April, with prices starting at £849 inc VAT – so that’s less cash than the VAIO for a higher-resolution screen inside a lighter device. Dell reckons the XPS 18 could be “the primary device in the house” – do you agree?